How to use the calculator
- Tap the keys or type on your keyboard. Digits, + - * / ^ ( ) % ! all work, and Enter or = gives the answer.
- Pick Degrees or Radians above the display before you use sin, cos, tan or their inverses. Degrees is the default.
- Function keys such as sin and โ open a bracket for you. Type the number, then press =. A bracket you forget to close is closed automatically.
- Press Ans to reuse your last answer, โซ to delete the last entry, AC to start over, or open Calculation history to reload one of your last 10 results.
How the calculator works
Your entry is read by a small expression parser built for this page, not by eval. It follows the standard order of operations: brackets first, then functions and factorials, then powers (right to left, so 2^3^2 is 2^9 = 512), then multiplication and division, then addition and subtraction. A minus sign in front of a power applies last, so -2^2 is -4. Implicit multiplication such as 2ฯ or 3(4+1) works. log is base 10 and ln is base e; the definitions follow the NIST Digital Library of Mathematical Functions, chapter 4.
The % key behaves like a phone calculator. After a plus or minus it means a percentage of the number before it, so 50 + 10% is 55 and 50 - 10% is 45. In other places it divides by 100, so 200 * 15% is 30. Results are rounded to 12 significant digits, which hides floating-point noise such as 0.1 + 0.2 = 0.30000000000000004 and shows 0.3.
Worked example with the starting display
The page opens with (12 + 8) ร 3 = and the answer 60: the bracket gives 20, and 20 ร 3 is 60. Try sin(30) in Degrees for 0.5, log(1000) for 3, 5! for 120 and sqrt(144) for 12. Switch to Radians and sin(ฯ) gives 0 instead of a long decimal.
Limits and edge cases
Division by zero, the square root of a negative number, log of zero and tan at 90 degrees show a plain message under the display and keep your entry so you can fix it. Factorials need a whole number from 0 to 170, because 171! is larger than a computer can store. Very large and very small answers show as aร10^n. History lives only in the open tab and clears when you close or reload the page. There are no memory keys, so use Ans. For exact fractions use the fraction calculator, for bigger factorials the factorial calculator, for percent problems the percentage calculator, and for powers of ten the scientific notation converter.
Calculator FAQ
Is this calculator in degrees or radians?
Degrees by default. Use the Degrees and Radians buttons above the display to switch. In Degrees, sin(30) is 0.5. In Radians, sin(30) is -0.988031624093, because 30 is read as 30 radians.
Does the calculator follow the order of operations?
Yes. It works through brackets first, then functions and factorials, then powers, then multiplication and division, then addition and subtraction. So 2 + 3 * 4 is 14, and (2 + 3) * 4 is 20.
How does the percent key work?
After a plus or minus, % means a percentage of the number before it, so 50 + 10% is 55 and 50 - 10% is 45. Anywhere else it divides by 100, so 200 * 15% is 30 and 15% on its own is 0.15.
What is the difference between log and ln?
log is the base-10 logarithm, so log(1000) is 3. ln is the natural logarithm with base e, so ln(1000) is 6.90775527898.
What is the largest factorial this calculator can find?
170!, which is about 7.2574 x 10^306. A browser cannot store 171!, so the calculator shows a message instead of a wrong answer.