Calculator
Free online calculator with an editable history tape, exact decimal mode (0.1 + 0.2 = 0.3), variables and list statistics. Keyboard-first, no ads.
Type an expression and press Enter — every line stays, and editing one line recalculates the rest.
Saved in this browser only — clearing site data or switching devices removes it. Use Export to keep a backup.
Desk: 100 + 10% = 110. Strict: 100 + 10% = 100.1.
Tape
Type an expression and press Enter. Every line stays and can be edited later.
Result
Your tape stays in this browser. Nothing is sent to a server.
How to use
- Type an expression such as 120000 * 3 and press Enter — the line and its result stay on the tape.
- Use ans for the line above, line3 for a specific line, or name a value with rent = 1500.
- Go back and edit any line — every line below it is recalculated instantly.
- Switch to Scientific for trigonometry and logs; check the DEG/RAD badge before using sin, cos or tan.
- Paste a column of numbers into Stats to get n, mean, median, quartiles and both standard deviations.
FAQ
Why is 0.1 + 0.2 not 0.3 on most calculators?
Because they store numbers in binary floating point, where 0.1 has no exact representation, so 0.1 + 0.2 lands on 0.30000000000000004. This calculator works with exact fractions for +, −, × and ÷, so it shows 0.3 — and keeps 1/3 as 1/3 instead of 0.333…. Switch the number mode to Floating point to see the raw binary result for yourself.
How does the % key work here?
Like a desk calculator: 100 + 10% is 110, because the 10% is taken of the 100 in front of it, and 100 − 10% is 90. In multiplication and division, and anywhere else, % simply means ÷ 100, so 100 × 10% is 10. Every line that uses % shows how it was read, for example 100 + (100 × 10%) = 110, and you can switch to the strict ÷ 100 convention in the settings.
Is −2^2 equal to −4 or 4?
−4. The exponent binds tighter than the minus sign, so −2^2 means −(2^2). Write (−2)^2 if you want 4. For the same reason 2^3^2 is 512, not 4096: powers group from the right. Every line shows the normalised reading underneath, so there is never a guess about how your input was parsed.
How do I switch between degrees and radians?
Use the DEG / RAD / GRAD badge at the top — the current unit is always visible, and changing it recalculates the whole tape. You can also force degrees on a single value with the ° suffix, so sin(30°) is 0.5 even in radian mode.
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