Scientific Calculator

How to use this scientific calculator

This calculator works like the physical one you used in school, with one improvement: you can see the whole expression as you build it. Type 2 + 3 * 4 and the top line shows exactly that, so you always know what is about to be calculated. Press the equals button or hit Enter and the answer appears in the large display. If you start typing a number right after an answer, the old calculation clears and a new one begins. If you press an operator instead, the answer carries over so you can keep chaining calculations.

Functions like sin, log, and the square root insert themselves with an open parenthesis, so you just type the value and close it. For powers, the x^y button inserts the power operator: 2, then x^y, then 10 gives 1024. The x^2 button is a shortcut that squares whatever came before it. Parentheses work the way you expect, and you can nest them as deep as you like. If you forget to close one, the calculator closes it for you when you press equals.

Degrees vs radians: which mode do you need?

The DEG button in the top-left corner switches between degrees and radians, and this is the single most common source of wrong answers on any scientific calculator. School geometry, navigation, and everyday angle problems use degrees: sin(30) in DEG mode is 0.5, which is the answer most people expect. Calculus, physics equations, and most programming languages use radians instead, where a full circle is about 6.283 rather than 360.

The rule is simple: match the mode to the problem. If the question talks about degrees, use DEG. If it talks about pi, or you are working through calculus homework, use RAD. The inverse functions (sin^-1, cos^-1, tan^-1) also follow the mode, so arcsin(0.5) gives 30 in DEG mode and about 0.524 in RAD mode. When an answer looks wrong, check this button before anything else.

Order of operations, done right

This calculator follows the standard order of operations: parentheses first, then powers and roots, then multiplication and division, then addition and subtraction. So 2 + 3 * 4 gives 14, not 20, exactly like it should. Powers stack to the right, which means 2^3^2 is 2^(3^2) = 512. You can also write numbers directly next to parentheses or constants and multiplication is assumed, so 2(3+4) and 2pi both work.

The percent button divides the number before it by 100, which is handy for quick percentage math. Factorials only accept whole numbers from 0 to 170; anything else shows Error, as do division by zero, square roots of negative numbers, and logarithms of zero or negative numbers. Error is never the calculator being broken. It is the calculator telling you the math itself has no answer.

Frequently asked questions

Should I use DEG or RAD mode?

Use DEG (degrees) for everyday geometry, school problems, and anything measured in degrees, like a 30 degree angle. Use RAD (radians) for calculus, physics formulas, and programming, where angles are measured in radians. If your sine or cosine answer looks wrong, the mode is the first thing to check.

How do I calculate a cube root?

Raise the number to the power of one third. For the cube root of 27, type 27, press the power button (x^y), open a parenthesis, type 1 / 3, close the parenthesis, and press equals. You get 3.

Why does the calculator show Error?

Error appears when the math has no valid answer: dividing by zero, taking the square root or logarithm of a negative number, taking the log of zero, or using a factorial on a negative number or a non-integer. Fix the input and calculate again.

What is the factorial limit?

Factorials work for whole numbers from 0 to 170. Beyond 170 the result is too large to represent, so the calculator shows Error. Note that 0! equals 1.

Is this scientific calculator free? Does it work offline?

Yes, it is completely free with no signup. Everything runs in your browser with JavaScript, so once the page has loaded it keeps working without an internet connection.