Calculator

#What it is

Calculator (app id calc) is Octoolo's calculator app: a calculator you can type into or click, with scientific keys and a history, plus 23 ready-made tools: 19 calculators and converters for everyday sums (units, percentages, fractions, dates, hours, loans, savings, school grades, BMI, calories) and four fair randomizers (a coin, dice, random numbers and a wheel of names). It does what many single-purpose calculator websites do.

Everything runs on the PC, offline. Calculator is free: it works without Octoolo Cloud (the free apps are listed in Prices and limits).

#Opening it and what it costs

• Calculator is free: no subscription or trial is needed. Without a subscription its tile on the home screen says Free. Which apps are free, and what the subscription costs: Prices and limits.
• On the home screen it is in the Utilities group. The home search finds it, and each tool, by words like "calculator", "percent", "loan", "gpa", "dice" or "time zone".
• Inside the app, the list on the left has the groups Calculate, Chance, Convert, Dates and time, Money, School and Health, and a Find box that filters the list. The app opens on Calculator ("Type or click. The answer shows as you go.").
• Addresses inside Octoolo: #/app/calc (the calculator), #/app/calc/calculator, and #/app/calc/<task id> for one tool (for example #/app/calc/loan). A shortcut can open it with Octoolo.exe --open=app/calc/<task id>.

#Tasks

The calculator itself (Calculator, address #/app/calc/calculator) and these 23 tasks, all working in version 0.8.0, in the order the app lists them:

Calculate

• Percentage calculator (percentage): X% of Y, X as a percent of Y, and percent change.
• Fraction calculator (fraction-calculator): add, subtract, multiply and divide fractions and mixed numbers, with the working shown; simplify a fraction; decimal to fraction.
• Discount calculator (discount): sale price, the saving, and tax on top.
• Tip & bill splitter (tip-split): the tip and each person's share.

Chance

• Flip a coin (coin-flip): heads or tails, one or up to 10,000 at once, with a tally.
• Roll dice (dice-roller): 1 to 100 dice of 4, 6, 8, 10, 12, 20 or 100 sides, with a total.
• Random number generator (random-number): whole or decimal numbers in a range, with or without repeats.
• Wheel of names (wheel-spinner): spin a wheel to pick a name; saved wheels.

Convert

• Unit converter (unit-converter): length, weight, temperature, area, volume and speed.
• Data size converter (data-size): bytes, KB, MB, GB, TB and PB, decimal or binary.
• Time zone converter (time-zones): one moment in other time zones.
• Roman numerals (roman-numerals): numbers to Roman numerals and back.
• Aspect ratio calculator (aspect-ratio): the ratio of a size, and the height for a new width.

Dates and time

• Date difference (date-difference): days, weeks, months and weekdays between two dates.
• Days from a date (date-add): the date a number of days, weeks, months or years before or after a day, working days too.
• Hours calculator (hours-calculator): time between two clock times, sums of hours and minutes, and a weekly timesheet.
• Age calculator (age): exact age from a date of birth.

Money

• Loan calculator (loan): the monthly payment and the total interest.
• Compound interest calculator (compound-interest): savings growth with deposits, a chart, a year-by-year table and inflation.

School

• GPA calculator (gpa-calculator): a grade point average from courses and credits.
• Grade calculator (grade-calculator): a weighted grade, and the score needed on the final.

Health

• BMI calculator (bmi): body mass index, metric or imperial.
• Calorie calculator (calorie-calculator): calories a day to keep, lose or gain weight.

Calculator has no tasks marked Coming.

#The calculator

The Calculator section is a calculator you type into or click:

1. Type a calculation in the box ("Type a calculation, such as 120 × 1.2 or 200 + 10%"), or click the keys. The answer shows under it as you type; halfway through ("3 +") it shows the answer so far.
2. Press Enter (or type =, or click the = key) to finish: the calculation goes into the History and the box holds the answer, ready to go on. After =, clicking a digit key (or ., (, π, e, √ or exp) starts a new calculation; clicking an operator key, x², 1/x, % or another function key goes on from the answer (a function after an answer means times: 12 then sin gives 12sin(, 12 × sin). Typing on the keyboard adds to what is in the box.
3. Esc (or clicking C) clears the box; ⌫ deletes the last character.

Keys: C, ⌫, %, ÷, ×, −, +, =, ± (puts a minus in front of the whole calculation, or takes it away), . and the digits. Scientific adds (, ), x², ^, √, π, e, ! (factorial), sin, cos, tan, 1/x, ln (natural log), log (base 10), abs and exp, and a Degrees/Radians switch for angles.

How it reads what you type:

• * and / work for × and ÷, ^ is "to the power of", pi for π, sqrt(…) for √. Typed functions also include asin, acos and atan.
• Percent works the way people expect: 200 + 10% is 220, 200 − 10% is 180, 200 × 10% is 20, and 10% alone is 0.1.
• A number next to a bracket, a constant or a function means times: 2π, 3(4+1), 2 sin(30).
• Brackets left open are closed for you.
• A comma is read as a decimal point (1,5 is 1.5), so write thousands without commas: 1000 or 1 000 (digits in groups of three with spaces are one number). 1,000 is read as 1.
• -2^2 is −4 (the power comes first).
• Answers show up to 12 significant digits (and at most 10 decimals), with thousands separators; very large (10^15 and more) and very small (below 0.000000001) answers are shown in e-notation (1.5e+20). Factorials above 170! are "Infinity".

Messages instead of an answer: "Nothing can be divided by zero.", "A factorial needs a whole number.", "“x” is not something a calculator knows." (a character or word it does not know), "The calculation ends too early.", "Something is missing in the calculation.", "Something does not add up in the calculation.", "Not a number" (for example the square root of a negative number), and "Infinity" or "−Infinity" (for example ln(0)).

History: the last 50 calculations, newest first ("Your calculations show up here. Click one to use it again."). Click one to put its calculation back in the box. The bin button ("Clear the history") empties it. The history and whether Scientific is on are remembered after Octoolo closes; angles start in Degrees each time.

It is not a programmer, graphing or financial calculator: no memory keys (M+, MR), no complex numbers, no hex/binary mode (Dev Toolbox's Number base converter converts bases: Dev Toolbox), no graphs, no equation solving and no unit arithmetic.

#Percentage, discount, tip and aspect ratio

• Percentage calculator (percentage): three lines, each answered as you type: "What is [15] % of [80] = 12"; "[30] is what percent of [120] = 25%"; "From [50] to [65] = +30%" (percent change; "—" when the first number is 0; a fall shows a minus).
• Discount calculator (discount): Price, Discount (%, 0 to 100) and Tax (%) give You pay (the discounted price plus tax), You save and Price after discount. Tax is added after the discount.
• Tip & bill splitter (tip-split): Bill, Tip (%) and People give Each pays, Tip and Total. The tip is a percent of the bill as typed; people are rounded to a whole number, at least 1.
• Aspect ratio calculator (aspect-ratio): Width and Height give the Ratio in smallest whole numbers (1920 × 1080 is 16 : 9) and As a number (1.7778); New width gives the matching height (to 2 decimals). It works from a new width only (for a new height, swap the numbers).

Money amounts show 2 decimals and no currency sign, so they work for any currency.

#Fraction calculator

Fraction calculator (fraction-calculator) works with exact fractions (no rounding, numbers of any size):

1. Each number has three boxes: a whole number on the left, and a fraction (top over bottom). Leave the whole number empty for a plain fraction, or the fraction empty for a whole number. A minus goes before the whole number (-1 1/2 is minus one and a half).
2. Pick +, −, × or ÷.
3. The answer shows as a Fraction, a Mixed number and a Decimal (up to 10 decimals), each with Copy, and How it is worked out lists the steps: turning mixed numbers into one fraction, finding the common bottom, adding (or subtracting) the tops, multiplying the tops and the bottoms, flipping the second fraction to divide, simplifying by the greatest common divisor, and writing the mixed number.

Below it:

• Simplify a fraction: a top and a bottom, simplified, with the greatest number that divides both, and the mixed number.
• Decimal to fraction: a decimal (0.375 is 3/8) as an exact fraction, simplified, with the mixed number, "The closest simple fraction is …" (bottom at most 100, for decimals such as 0.333) and "To the nearest sixteenth: …" (for measurements). Up to 30 digits after the point.

Messages: "Fill in both numbers: a whole number, a fraction, or both. The bottom cannot be 0.", "Dividing by zero has no answer.", "Type whole numbers, and not 0 at the bottom.", "Type a decimal number, like 0.375 or 2.5."

#Unit, data size, time zone and Roman numeral converters

Unit converter (unit-converter): pick the Measure, type a Value, pick the unit it is From; every other unit of that measure is listed with Copy (up to 6 decimals; very small values to 6 significant digits).

It has no currency converter (exchange rates need the internet), and no pressure, energy, power, time, angle, fuel economy, pints, quarts or UK fluid ounces.

Data size converter (data-size): a Size and its Unit (B, KB, MB, GB, TB or PB), shown in all six (up to 4 decimals; values below 0.001 to 6 significant digits), each with Copy. By default 1 KB = 1,000 bytes; Binary (1 KB = 1024 bytes, as Windows counts) uses 1,024 and labels the units KiB, MiB, GiB, TiB, PiB. (This is why a "1 TB" drive shows as about 931 GB in Windows.)

Time zone converter (time-zones): a Date and time In a time zone (the PC's own at first), shown in a list of other zones: UTC, America/New York, Europe/London, Europe/Istanbul and Asia/Tokyo at first (the PC's own zone is left out). ✕ removes a zone; Add a time zone adds one from every IANA time zone the PC knows (by region/city name, such as Europe/Paris or Australia/Sydney). Summer time (daylight saving) is applied for the date chosen. The list goes back to the default zones each time the tool is opened.

Roman numerals (roman-numerals): type a number (1 to 3999) to get the Roman numeral, or a Roman numeral to get the number, in Number or Roman numeral. Only standard forms are read (IV, not IIII), in capitals or small letters. Messages: "Roman numerals go from 1 to 3999.", "That is not a Roman numeral."

#Date difference and days from a date

Date difference (date-difference): a From and a To date (today and 30 days later at first; their order does not matter) give:

• Days: the days from one to the other. Count the last day too adds one, so both the first and the last day count.
• Weeks: whole weeks and days ("4 w 2 d").
• Calendar: years, months and days as a calendar counts them ("1 year, 2 months, 3 days"; a month from the 31st ends on a shorter month's last day).
• Weekdays: the Mondays to Fridays in the span, counting the first day and not the last (both with Count the last day too). Public holidays are not taken into account: Octoolo has no holiday calendar for any country.

Days from a date (date-add): the date a number of days, weeks, months or years after or before a day.

• Start date (with Today), Direction (After or Before), How many, Unit (Days, Weeks, Months, Years).
• Working days only (skip Saturdays and Sundays) (for Days only): counts Monday to Friday; the start day is not counted. The app notes "Public holidays are not skipped: add one day for each holiday that falls in between."
• The answer, written out, and Date (YYYY-MM-DD), Written out, Week number (ISO weeks: "Week 41 of 2026"), From today ("In 30 days", "12 days ago", "Today") and, with working days, Calendar days, each with Copy.
• Adding months or years to the 29th, 30th or 31st lands on the last day of a shorter month: "That month has no 31st, so the answer is its last day."
• Quick answers: 7, 14, 30, 60, 90 and 180 days, 6 months and 1 year from (or before) the start date; clicking one sets it.
• Messages: "Pick a start date.", "That is further than the calendar goes. Try a smaller number." (more than 700,000 days, 100,000 weeks, 24,000 months or 2,000 years).

Age calculator (age): Date of birth and Age on (today at first) give Age (whole years), Exactly (years, months and days), Days lived and Next birthday ("in 45 days", or "Today 🎉"). A birth date after the other date shows "The date of birth is after that day."

#Hours calculator and timesheet

Hours calculator (hours-calculator) has three parts (What to work out):

Between two times: Start, End and Break (minutes) give the time without the break as hours:minutes (8:00), Decimal hours (8.00) and Minutes (480), each with Copy. An end earlier than the start counts as past midnight (a night shift: 22:00 to 06:00 without a break is 8:00). It starts at 09:00 to 17:30 with a 30-minute break. Messages: "Fill in both times.", "The break is longer than the time between the two."

Add and subtract: lines of lengths of time, each with + or −. Write 1:30, 1:30:00, 1h 30m, 90m, 1.5h, 2d 4h, 45s, or a number alone for hours (1.5 is 1 hour 30 minutes); a comma works as a decimal point. Add a line adds one; ✕ removes one. The Total shows as hours:minutes, decimal hours and minutes (and "That is 2 days and 3:15." past 24 hours). Start from a clock time shows the clock time after the total ("→ 17:45", "the next day"). A line it cannot read: "Line 2 is not a length of time. Write it like 1:30, 1h 30m, 90m or 1.5h."

Timesheet: one week, Monday to Sunday, each with Start, End and Break (min); Hours per day (with "overnight" for a shift past midnight). It starts with Monday to Friday 09:00 to 17:30 with a 30-minute break. Pay per hour ("Leave empty for hours only") adds Pay. The total shows as This week (hours:minutes) and Decimal hours. Copy table copies the week (day, start, end, break, hours and decimal hours) with a total line as tab-separated text that pastes into Excel or Spreadsheets as cells (the pay is not in it); Clear empties every day (the pay per hour stays). "The week is kept on this computer, so it is still here next time."

The timesheet holds one week only (no history of past weeks), has no overtime rules or rounding, and does not print or save files (copy it into a spreadsheet).

#Loan and compound interest

Loan calculator (loan): Amount, Interest per year (%) and Term (years, in steps of 0.5) give the Monthly payment, Total paid and Total interest, for a standard loan repaid in equal monthly payments (interest monthly, at the yearly rate ÷ 12). With 0% interest the payment is the amount ÷ the months. It does not show an amortization table, extra payments, fees, taxes or insurance.

Compound interest calculator (compound-interest):

• Starting amount, Deposit (each A month or A year), Interest a year (%), Interest added (Daily, Monthly, Quarterly, Twice a year, Yearly or Continuously), Years (1 to 100) and Inflation a year (%, "0 leaves it out").
• Deposit at the start of each month (not the end) (or "of each year").
• Results: After 10 years (the balance at the end; the label follows Years), You put in (the starting amount plus the deposits), Interest earned, and either In today's money (when inflation is set: the balance divided by the inflation over the years) or Yearly rate with compounding (APY). Each has Copy.
• A chart of the balance each year, paid in and interest stacked (point at a year to see its numbers), and a Year by year table (paid in and interest that year and so far, balance, and, when inflation is set, in today's money) with Copy table (tab-separated, for spreadsheets).
• How it counts: between deposits the money grows at the yearly rate compounded as chosen (daily interest with monthly deposits grows by (1 + r/365)^(365/12) a month), the usual way banks' illustrations work it out. More than 100 years: "Up to 100 years."

Neither tool is financial advice, and neither accounts for taxes or fees.

#GPA calculator and grade calculator

GPA calculator (gpa-calculator) uses the usual US 4.0 scale:

• Courses: a name, Credits (steps of 0.5) and a Grade; Pass (not counted) and Withdrawn (not counted) are left out, and so is a course with no credits. Add a course adds a row; ✕ removes one; Start over leaves one course with no name (3 credits, grade A). It starts with four example courses.
• A+ counts as 4.3: for schools that give A+ more than A.
• Weighted (honors +0.5, AP or IB +1): adds a Level column (Regular, Honors, AP or IB); the bonus is added to passing grades only (an F stays 0).
• Results: GPA this term (or Weighted GPA this term, with Unweighted beside it), Credits counted and Grade points (credits × points), to 2 decimals.
• With earlier terms: GPA so far and Credits so far give the Cumulative GPA (credit-weighted).
• "Schools differ: check yours for A+ and for how they weight honors and AP classes. Your courses are kept on this computer."

It has only the US letter-grade scale: no percentage-based, 10-point (India), UK class or other national scales.

Grade calculator (grade-calculator):

• Parts of the grade: a name, a Weight (%) and a Score for each part (homework, quizzes, midterm, final). A score is a percentage (92 or 92%) or points (45/50, 45 of 50, 45 out of 50); leave it empty ("Not yet") for a part still to come. The table's header shows the total ("Weights add up to 85%"), marked when it is not 100%. Add a part adds one; ✕ removes one.
• Results: Grade so far (the graded parts, each by its weight, as a percent of what is graded), Letter (common US scale) (93 A, 90 A−, 87 B+, 83 B, 80 B−, 77 C+, 73 C, 70 C−, 67 D+, 63 D, 60 D−, below 60 F) and Of the course graded (the weights of the parts that have a score).
• What do I need on the final?: with Use the parts above on (the default), the grade so far and the weight still to come (the parts without a score) come from the table; off, type Grade so far and The final is worth yourself. Set Grade I want (90% at first) and it answers "To finish with 90% you need" and the score "on the final" (with the example parts: 98.38% on the final), plus the scores needed For 90%, For 80%, For 70% and For 60%. More than 100% says "More than 100%: out of reach without extra credit." (in the list: "…: out of reach"); 0 or less says "0% (already there)".
• When every part has a score: "Every part has a score, so nothing is left to take. Empty the final's score, or switch off “Use the parts above”."
• The needed score is (grade wanted − grade so far × (1 − final's weight)) ÷ final's weight.
• A score it cannot read: "The score of Midterm is not a percentage or points like 45/50."

#BMI and calorie calculator

BMI calculator (bmi): Units cm, kg or ft, lb; Height and Weight give the BMI (to one decimal) and the Category (adults): below 18.5 Underweight, below 25 Healthy weight, below 30 Overweight, 30 and over Obesity. The app notes: "BMI is a rough guide for adults and does not account for muscle, age or build." It has no children's BMI percentiles.

Calorie calculator (calorie-calculator) estimates daily calories with the Mifflin-St Jeor equation (1990):

• Inputs: Units (cm, kg or ft, lb), Sex (Female or Male), Age (15 to 100), Height, Weight and How active you are:

  Choice	Factor
  Sitting most of the day, little exercise	1.2
  Light: exercise 1 to 3 days a week	1.375 (default)
  Moderate: exercise 3 to 5 days a week	1.55
  Very active: hard exercise 6 or 7 days a week	1.725
  Extra active: a physical job and training	1.9

• At rest (BMR) = 10 × weight in kg + 6.25 × height in cm − 5 × age + 5 (male) or − 161 (female). Calories a day to stay at this weight = BMR × the activity factor.

• A table of calories a day to Lose 1, 0.75, 0.5 or 0.25 kg a week, Stay at this weight, or Gain 0.25 or 0.5 kg a week (in pounds: lose 2, 1.5, 1 or 0.5 lb, gain 0.5 or 1 lb), counting 7,700 kcal per kg (3,500 per lb). Under 1,500 (male) or 1,200 (female) a day is marked "Very low: ask a doctor first". Each has Copy.

• An age outside 15 to 100: "The equation is made for adults: an age from 15 to 100."

• The app says it is "An estimate from the Mifflin-St Jeor equation, not medical advice" and to ask a doctor or dietitian when pregnant, breastfeeding, under 18 or living with a health condition.

It does not track food, count macros or keep a weight log.

#The randomizers: coin, dice, numbers and wheel

In Calculator's randomizers, every draw comes from the PC's cryptographic random generator, drawn so that no result is more likely than another (no "modulo bias"). The animations are only for show: the result is drawn first. When Windows' animation effects are turned off, the coin, dice and wheel show their result at once.

Flip a coin (coin-flip): Flip (or click the coin) flips one; Flip several at once flips 1 to 10,000 coins and shows "6 heads, 4 tails". The tally shows Heads and Tails (with percentages), Flips and In a row (the current streak). Last flips, newest first (the last 200 kept, 120 shown) has Copy and Start over (which also resets the tally).

Roll dice (dice-roller): Dice (1 to 100), Sides (d4, d6, d8, d10, d12, d20 or d100) and Add to the total (a modifier, plus or minus). The roll button (named after the roll: Roll 2d6 at first, Roll 3d20 + 2 and so on) or a click on the dice rolls; the total, the dice added up, Lowest possible, Highest possible and Average show, and Rolls, newest first keeps the last 50 (with Copy and Clear). Changing the dice or sides rolls the new set at once (that roll is not added to Rolls). Only those seven kinds of dice: no d2, d3, d30 or other side counts, and no dice notation typed in (like "4d6 drop lowest").

Random number generator (random-number): From, To (both included; their order does not matter), How many (1 to 10,000), Kind (Whole numbers or Decimals with 1 to 10 Decimal places), No repeats (on by default) and Sort from low to high. Quick ranges: 1 to 10, 1 to 100, 1 to 1,000, 6 from 1 to 49 and 5 from 1 to 69 (lottery-style, sorted, no repeats). Generate again draws anew, and so does changing a setting. One number shows big, with Copy, "Each of the 100 possible numbers had a 1 in 100 chance." and the earlier draws (up to 12); several show in a grid (the first 2,000 on screen) with Copy with commas and Copy as lines (all of them). Messages: "Fill in both ends of the range.", "There is no number between those two.", "Only 49 different numbers fit between 1 and 49. Ask for fewer, or allow repeats.", "That range is too wide for this many decimals. Use fewer decimals or a smaller range."

Wheel of names (wheel-spinner):

• Names, one per line (blank lines are skipped; the count shows beside the title). A name written twice gets two slices, so it is twice as likely; every slice is equally likely.
• Spin (the button in the middle) or click the wheel: it spins for about 6 seconds, with clicks as it passes each slice (Click as it spins, on by default), then "The wheel picked" the winner, with Spin again, Remove <name> (Remove the winner for a name over 18 characters; takes the winner off the list, for picking everyone in turn; needs at least 3 names) and Copy.
• There is no set limit on names. With more than 339 names the slices are too thin for their names to be written on them (the winner is still named under the wheel); a long name is cut short with "…" on its slice.
• Shuffle, Sort A to Z and Clear change the list. Ready-made wheels: Yes or no, Yes, no or maybe, 1 to 10 and Example names.
• Saved wheels: Save this list as a name (up to 60 characters) and Save (or Replace for a name already used); Open a saved wheel picks one; Delete removes it.
• Picked so far: the winners of this visit (last 100), with Copy and Clear.
• With fewer than two names: "Put at least two names in the list."
• "Names and saved wheels are kept on this computer."

The wheel has no weights per name, pictures, colors to choose, or full-screen mode.

#Options and settings

Calculator has no settings page. Each tool's own switches are described with the tool above. What is remembered between visits is listed in "Where it keeps things"; everything else starts with its defaults each time a tool is opened.

#Keyboard shortcuts

Clicking the calculator's keys keeps the typing cursor in the box, so typing and clicking mix.

#Where it keeps things

These are kept in the storage of Octoolo's window (WebView2), in Octoolo's data folder %LOCALAPPDATA%\com.octoolo.app, and are still there the next time Octoolo opens:

• the calculator's history (last 50);
• whether Scientific is on;
• the timesheet's week and its pay per hour;
• the GPA calculator's courses, and A+ counts as 4.3 and Weighted;
• the grade calculator's parts;
• the wheel's names, the saved wheels, and Click as it spins.

Everything else (the calculation in the calculator's box, Degrees/Radians, the other tools' numbers, the time zone list, the coin and dice tallies, the random numbers, the wheel's "Picked so far", "With earlier terms", the final-grade settings) is forgotten when the tool is closed or another tool is opened.

What is kept is lost when:

• Octoolo is uninstalled with the uninstaller's "Delete the application data" box ticked (an ordinary uninstall keeps it), or the %LOCALAPPDATA%\com.octoolo.app folder is deleted;
• the person uses another Windows account or another PC: it is kept per Windows user on one PC and is not synced, backed up or tied to the Octoolo account;
• the person clears it in the app (Clear the history, the timesheet's Clear, Start over, Delete a saved wheel).

Octoolo has no export or backup for these; copy what matters (Copy table, Copy).

#Downloads it needs

None. Calculator works offline from the first start.

#Privacy

Nothing leaves the PC. Calculations, dates of birth, weights, grades, pay and names on the wheel stay in the app on the computer. Octoolo's usage statistics (if left on) note which tools are opened, never the numbers typed: see Privacy and data.

#Troubleshooting

#Calculator gives a wrong answer for 1,000 or 2,5

In Calculator, a comma is read as a decimal point, so 1,000 is 1, 2,5 is 2.5, and 1,000,000 is 0 (read as 1 times 0.000). Type thousands without commas (1000, or 1 000 with a space). The answer itself is shown with thousands separators, so do not type an answer back in as it is shown: after = (or Enter) the box already holds the answer without separators, ready to go on.

#"200 + 10%" gives 220, not 200.1

That is by design: Calculator treats a percent after + or − as a percent of the number before it, like a shop till: 200 + 10% is 220. For 10% as a plain number, type 0.1 or 10/100.

#sin, cos or tan give unexpected values

In Calculator, angles are in Degrees by default. For radians, turn on Scientific and press Degrees to switch it to Radians. It starts in Degrees each time Calculator is opened.

#"“x” is not something a calculator knows."

The calculation has a character or word Calculator does not know (for example a currency sign, a letter, or x used for times). Use * or × for times, and only numbers, operators, brackets, pi, e and the functions listed in "The calculator".

"“nan” is not something a calculator knows." or "“infinity” is not something a calculator knows." right after Enter means the answer was "Not a number" or "Infinity" (for example the square root of a negative number, or 171!): the box then holds that word, which cannot be calculated with. Press Esc and start again.

#The working days count does not match my company's

Date difference and Days from a date skip only Saturdays and Sundays. Public holidays are not known for any country: take one day off the count for each holiday in the span (or add one day for each holiday when adding working days). Weekdays in Date difference count the first day and not the last, unless Count the last day too is on.

#My GPA does not match my school's

Calculator uses the common US 4.0 scale (A 4.0, A− 3.7, B+ 3.3 and so on). Check whether your school gives A+ 4.3 (A+ counts as 4.3) and how it weights honors and AP classes (Weighted). Pass and Withdrawn courses are not counted. Other countries' scales are not built in.

#The wheel, the timesheet or my courses are empty after reinstalling or on another PC

They are kept only on the PC where they were made (in Octoolo's local data). They are lost if the uninstaller's "Delete the application data" box was ticked, and they do not move to another PC or Windows account. Octoolo cannot recover them.

#The coin or the wheel always seems to land the same way

Each flip, roll and spin is drawn independently from the PC's cryptographic random generator, with no result more likely than another; streaks happen by chance. On the wheel, check the list for names written twice (each copy is a slice).

#"Only 49 different numbers fit between 1 and 49. Ask for fewer, or allow repeats."

With No repeats on, How many cannot be more than the numbers in the range. Ask for fewer, widen the range, or turn No repeats off.

#Limits and what it cannot do

• It cannot convert currencies or use live data of any kind: everything works offline.
• It knows no public holidays (working days skip weekends only).
• It is not a graphing, programmer or financial (TVM) calculator, and has no memory keys.
• The unit converter has six measures only (length, weight, temperature, area, volume, speed).
• The dice are d4, d6, d8, d10, d12, d20 and d100 only.
• The GPA calculator has the US 4.0 scale only.
• The timesheet is one week, without overtime or rounding rules, and cannot be printed or saved as a file.
• Nothing is synced between PCs, and there is no export or backup of the saved lists.