Scientific Calculator

Instead of tapping keys, you write expressions the way they appear in a textbook and the answers appear on the right.

1. Type one calculation per line in the input box, for example 2 * (3 + 4)^2. The result appears beside it in the form expression = result.
2. Choose Angles in: Degrees or Radians. This affects sin, cos, tan and their inverses only.
3. Set Decimal places from 0 to 12. The default is 8, and long decimals are rounded for display.
4. Write ans on a later line to reuse the result of the line above, so ans / 4 divides the previous answer by four.
5. Read the note under the box, which counts the lines calculated and any with errors. A bad line shows its own message and the lines around it still work.

Blank lines are left blank, so you can space your working out into groups. Brackets can be nested as deeply as you need, and spaces around operators are optional.

Multiplication, division, minus and pi can also be typed as ×, ÷, − and π.

The parser follows the usual order of operations: brackets first, then powers, then multiplication and division, then addition and subtraction. Three details catch people out. A power is worked right to left, so 2^3^2 is 2 to the power 9, which is 512. A minus sign binds more loosely than a power, so -2^2 is -4, and (-2)^2 is 4. The factorial sign ! and the percent sign % follow the number they apply to.

Built-in constants are pi, e, tau (2 pi) and phi (the golden ratio).

Every function needs brackets, and functions with two inputs separate them with a comma.

• Trigonometry: sin, cos, tan, asin, acos, atan, sinh, cosh, tanh, plus rad and deg to convert between the two angle units.
• Roots and logs: sqrt, cbrt, ln (natural), log (base 10), log2 and exp.
• Rounding and sign: abs, floor, ceil, round, trunc and sign.
• Two or more inputs: pow(a, b), mod(a, b), min, max and hypot.
• Factorial: fact(n) or n!, for whole numbers from 0 to 170.

For quick fractions rather than decimals use the fraction calculator, and for a list of values the average calculator is faster than typing a long sum.

The percent sign only divides by 100, so 50% is 0.5 and 100 + 10% is 100.1, not 110. To add ten percent write 100 * 1.1, or use the percentage calculator. There is also no remainder operator, so write mod(10, 3) instead of 10 % 3.

Computers store decimals in binary, so tiny errors appear in the background. Results are tidied before display, which is why 0.1 + 0.2 shows 0.3. Sine and cosine results that should be exactly zero, such as sin(180) in degrees, are snapped to 0, and tan(90) is reported as undefined. Very large results switch to exponent form, and 2^100 shows 1.2676506e+30 at 8 places.

• There is no implicit multiplication, so write 2*pi, not 2pi.
• The only name you can define is ans; there are no other variables.
• Complex numbers are not supported, so sqrt(-4) returns an error.
• Factorials above 170 and divisions by zero are reported as errors on their own line.

Errors are shown beside the line that caused them, for example a missing closing bracket, an unknown name or a logarithm of zero, and the remaining lines keep calculating. That makes it practical to build a small worksheet: put one sum on each line, fix the one that fails and carry on. The calculator is meant for everyday and school-level arithmetic, and it is not a replacement for a computer algebra system or for software that needs exact symbolic results.

To view results in another number system, send whole numbers to the number base converter.