Scientific Calculator

Everyday & learning

Full scientific calculator, operable from the keyboard.

Result
512

The answer updates as you type. Press Calculate, or Enter, to keep a line in the history below.

Insert

How to use

What it's for

Work out sums too long for a phone calculator — powers, roots, trigonometry, logarithms, factorials — typed as one line and answered as you type.

Before you start

Have the sum written down, and know whether its angles are in degrees or radians. Use * for times and / for divide; brackets work as they do on paper.

  1. Type the sum

    Type it in Expression, such as (1+2)*3^2 - sqrt(16)/2. On a phone, the keys under Insert add things like sin, √ and π where the cursor is.

  2. Choose the angle unit

    Pick Degrees or Radians to match your problem. It only affects sin, cos, tan and their inverses.

  3. Read the answer, then keep it

    The answer shows at the top as you type. Press Calculate, or Enter, to file the line into History below — that is all the button does, because the answer is already there.

  4. Reuse a line or start over

    Tap a line in History to bring it back for editing. Clear empties the expression; Clear history empties the list, which is kept only while the page is open.

Reading the result

  • Result: the answer to the whole line. It reads Not a valid expression while the sum is unfinished or has a mistake in it.
  • Under a mistake, the message names the problem and repeats the sum with ^ marks under the spot that went wrong.
  • History: the lines you kept, newest first, each with its answer. A line marked · rad was worked in radians.

If it goes wrong

  • -2^2 gives -4: the minus applies after the power. Type (-2)^2 if you mean minus two, squared.
  • 2^3^2 gives 512, not 64: powers are worked from the right. Add brackets, (2^3)^2, for the other reading.
  • tan(90) or 1/0 shows an error: the answer is genuinely undefined, not just a very big number. Check the sum — and, for an angle, whether Degrees or Radians is selected.

What this is

Type an expression and read the answer: it is on screen before you reach for a key. Calculate, or Enter, keeps the line in the history.

Where calculators disagree with each other, this page says which side it takes rather than leaving you to find out. 2^3^2 is 512, not 64. -2^2 is −4, not 4. 1/2x is half of x, not the reciprocal of 2x. Each of those has a defensible other reading, and the difference between them is not small.

It also declines to answer where there is no answer. tan(90) is undefined and says so; it does not return a number in the quadrillions. So does dividing by zero, the logarithm of a negative, and the arcsine of two. A calculator that answers "Infinity" has told you nothing and hidden which step went wrong.

Questions

Why is 2^3^2 equal to 512 and not 64?

Because powers group from the right: 2^3^2 means 2^(3^2) = 2^9 = 512. Reading it left to right would give (2^3)^2 = 64. Both answers exist in the wild, which is why it is worth knowing which one you are looking at. Use brackets if you mean the other.

Why is -2^2 equal to -4?

Because the minus sign binds looser than the power, so it reads as -(2^2). This matches every scientific calculator and every programming language except spreadsheets — Excel gives 4 here and is essentially alone. Type (-2)^2 if you want the square of negative two.

What does 1/2x mean here?

Half of x. Implicit multiplication — writing 2x instead of 2*x — binds at exactly the same strength as an explicit divide, and evaluation runs left to right, so 1/2x is (1/2)·x. Some physics papers use the opposite convention where it means 1/(2x). The two differ by a factor of x², so use brackets whenever it matters.

Why does sin(180) give exactly 0 here when other calculators show 1.2e-16?

Because π cannot be written exactly in binary, so the usual computation of sin(180°) lands a hair away from zero. The tiny number is not wrong, but it is not an answer either. In degree mode this calculator recognises the exact quarter turns and returns the exact value. Nothing else is rounded — a genuinely small result stays small.

Why does tan(90) give an error instead of a huge number?

Because the tangent of 90° is genuinely undefined — the line is vertical and has no slope. Answering "Infinity", or a number in the quadrillions, would suggest there is a value there. The same applies to dividing by zero, the logarithm of a negative number, and the arcsine of anything outside −1 to 1.

Is there an equals key?

Yes — Calculate, beside the angle switch. The answer already updates as you type, so pressing it (or Enter) keeps the current line in the history below, and clicking any history line brings it back for editing.

Can I use it entirely from the keyboard?

Yes, and that is the intended way. Type the expression, read the answer, press Enter to keep it. The keypad exists for phones. It also accepts the × ÷ − symbols from a phone keyboard, and π and √ if you have them.

How it reads an expression

Strongest first
brackets, functions
x!
^  right to left
−x  looser than the power
× ÷  and implicit, left to right
+ −
The three disagreements
2^3^2 512
-2^2 −4
1/2*3 1.5

Every one of these is 64, 4 or 0.1667 on some calculator somewhere. Brackets settle the argument in every case, and cost nothing.

What it knows

sin cos tan asin acos atan
sinh cosh tanh
sqrt cbrt abs exp ln log log2
floor ceil round sign mod min max
npr ncr   x!   pi e tau

Keep going

Important

Results are computed in double-precision floating point and displayed to twelve significant figures. Nothing you type here is sent to our servers — the calculation runs entirely in your browser.