Online calculator

A simple calculator with a scientific side

This online calculator handles everyday sums: addition, subtraction, multiplication, division and percentages. One button opens the scientific calculator keys, with brackets, powers, roots, trigonometry and logarithms, much like the calculator you used at school. The display has two lines: the calculation you are typing on top, the result underneath.

How to use it

1. Type your calculation with the on-screen keys or your keyboard.
2. Press = or Enter: the result shows in large digits and is added to the "History".
3. To carry on from that result, type an operator straight away: 14 then × 2 gives 28. Typing a digit starts a new calculation.
4. "Scientific mode" shows or hides the advanced functions. "Copy result" puts the answer on your clipboard.
5. In the "History", tap a line to reuse its result. Your last 20 calculations stay on this device until you press "Clear history".

Keyboard shortcuts: digits, + - * / ^ ( ) %, ! for factorial, a point or a comma for decimals, Enter or = to calculate, Backspace to delete the last character, Esc to clear everything.

Order of operations: PEMDAS and BODMAS

The calculator follows the rule taught at school, called PEMDAS in the US and BODMAS (or BIDMAS) in the UK: brackets first, then powers, then multiplication and division, then addition and subtraction, working left to right.

• 2 + 3 × 4 = 14, because 3 × 4 is worked out first;
• (2 + 3) × 4 = 20;
• 10 − 4 ÷ 2 = 8;
• 2 × 3² = 18, and −3² = −9: the square comes before the minus sign.

A bracket you forget to close at the end is closed for you when you press =. Multiplication can be implied: 2π and 3(4 + 1) both work.

Working out percentages with the % key

The % key works the way pocket calculators do, with two uses.

• Taking a percentage: 200 × 15 % = 30. After × or ÷, 15 % simply means 0.15. Handy for a 15 % tip on a $200 bill.
• Adding or removing a percentage: 200 + 10 % = 220 and 80 − 25 % = 60. After + or −, the percentage applies to the number before it: a 10 % rise or a 25 % discount in one line.

Scientific functions for school and beyond

In maths lessons the most useful keys are x² and √ for Pythagoras: √(3² + 4²) = 5. xʸ raises to a power (2 ^ 10 = 1024), 1/x gives the reciprocal and n! the factorial (5! = 120). log is the base-10 logarithm (log(1000) = 3) and ln the natural logarithm (ln(e) = 1), with their inverses 10ˣ and eˣ. MC, MR, M+ and M− handle a memory, and Ans recalls the last answer.

Errors are spelled out instead of giving a wrong number: division by zero, the square root of a negative number, or an incomplete expression such as "5 +".

Degrees or radians

Pick "Degrees" or "Radians" above the functions. In degrees, sin(30) = 0.5 and cos(60) = 0.5. In radians, cos(π) = −1. If sin(30) shows −0.988031624093, you are in radians. sin⁻¹, cos⁻¹ and tan⁻¹ return an angle in the chosen unit: sin⁻¹(0.5) = 30 in degrees.

Why you will not see 0.30000000000000004

Computers store numbers in binary, where 0.1 cannot be written exactly. That is why many programmed calculators show 0.1 + 0.2 = 0.30000000000000004. Here, every operation is rounded to 15 significant digits and the answer is shown with at most 12: 0.1 + 0.2 = 0.3 and 1.1 × 3 = 3.3. √2 displays as 1.41421356237.

For guided calculations, the site also has a percentage calculator and a rule of three calculator.

Frequently asked questions

Does the calculator work on a phone?

Yes. The keys are large and the tool stays usable on a 360-pixel screen.

Why does 200 + 10 % give 220 and not 200.1?

After + or −, the % key takes the percentage of the number before it, as a pocket calculator does. To add 0.1, type 200 + 0.1.

Is my history sent anywhere?

No. It is kept in your browser's storage on this device. "Clear history" deletes it.

What is the largest factorial it can show?

170! is the last one that fits, about 7.25741561531E306. Beyond that, the display says "Number too large".