Scientific calculator

Trig, log, square root and other scientific operations.

Trigonometric functions use radians. For degrees (°), multiply by deg (e.g. sin(45 deg)).

You are halfway through a homework problem or a quick estimate when a sine, a logarithm or a square root shows up, and the calculator on your phone runs out of buttons. Installing another app for a two-minute job is more trouble than it's worth.

This tool takes a different approach: you type the expression as a single line, exactly as you would write it. Something like (3+4)*sqrt(2)^2 works fine, and the result updates while you type. The keypad below the input is there to save keystrokes, not to replace typing.

How it works

Write the whole expression on one line

Type directly into the input field. Tapping a keypad button appends that symbol after the cursor rather than starting a new calculation. Pressing = (or Enter) moves the result into the input box so you can keep working from it, ⌫ deletes one character and C clears everything.

If the display shows = ?, the expression could not be parsed. In almost every case it is an unmatched parenthesis, two operators in a row such as 3++4, or a misspelled function name. Deleting one character at a time is the fastest way to find it.

Angles are in radians

sin(45) means the sine of 45 radians, not degrees. To work in degrees, add deg after the number:

You want	Type
sin 45°	`sin(45 deg)`
cos 60°	`cos(60 deg)`

Logarithms need an explicit base

Both the log and ln buttons compute the natural logarithm. If you need a different base, state it:

You want	Type
Natural log of 100	`ln(100)` or `log(100)`
Base-10 log of 100	`log10(100)` or `log(100, 10)`
Base-2 log of 8	`log2(8)`

Things worth knowing

! is factorial: 5! gives 120.
% is read from context. 10 % 3 is a remainder (1), while 100 + 10% is a percentage (110).
The comma separates function arguments. It is not a thousands separator, so 1,234 is not a single number - type 1234.
pi gives π and e gives Euler's number. ^ raises to a power.

Everything runs inside your browser, and the expressions you type are never sent to a server.

Terms explained

Radian: A unit of angle measured along the arc of a circle. 180 degrees equals π radians, and this calculator uses radians by default.
deg: A suffix that converts a number from degrees to radians. Write it after the number with a space, as in 45 deg.
Natural log (ln): A logarithm with Euler's number e as its base. On this calculator the log button does the same thing.
Factorial (!): The product of every whole number from 1 up to the given number. Common in probability and combinatorics.
sqrt: The square root function. Pressing the √ key inserts sqrt( for you.
Expression parser: The component that reads your typed line and works out the order of operations. When it cannot read the line, you see = ?.

Frequently asked questions

Why doesn't sin(45) give 0.7071?

Because trigonometric functions default to radians, sin(45) is the sine of 45 radians. For degrees, add deg after the number: sin(45 deg). The same applies to cos and tan.

Is the log button base 10?

No. Both log and ln compute the natural logarithm. For a base-10 result type log10(100) or log(100, 10). For base 2, use log2(8).

Can I type numbers with thousands separators?

No. The comma is reserved for separating function arguments, as in log(100, 10). Enter numbers without commas, so 1234 rather than 1,234.

The result just shows = ?. What went wrong?

That means the expression could not be parsed. Usually a parenthesis is unmatched, two operators sit next to each other, or a function name is misspelled. Remove characters one at a time to locate the problem.

Can I continue calculating from a previous result?

Yes. Press = or Enter and the result moves into the input field. Add an operator after it and the next calculation continues from that value.