How to use
- Enter numbers and operators with the buttons or your keyboard, then press = or Enter.
- ± changes the sign of the last number you typed: 5 becomes −5, and 3×5 becomes 3×(−5). Press it again to change it back.
- ⌫ deletes the last character and AC clears the whole expression.
- After a result, press +, −, × or ÷ to keep calculating with it, or type a number to start a new calculation.
- On a keyboard, use the digits, ., + - * /, %, Enter or = (equals), Backspace (delete) and Escape (clear).
- Need trigonometry, logarithms or parentheses? Press Scientific calculator at the top. Your expression carries over.
How the % key works
On its own, a percent is divided by 100: 50% = 0.5. With × it gives a share of a number: 200×10% = 20, which is 10% of 200.
After + or −, the percent is taken of the number before it. 200+10% adds 10% of 200 to give 220, and 200−10% takes it off to give 180. This is the quickest way to add sales tax or a tip, or to take off a discount.
Worked examples
- Sales tax: a $45.99 item with 8.25% tax costs 45.99+8.25% = 49.784175, or about $49.78.
- Tip: an 18% tip on a $64 bill gives 64+18% = 75.52, so the total is $75.52.
- Splitting the bill: right after that result, press ÷ 4 = to get 18.88, or $18.88 each.
- Discount: 25% off $80 is 80−25% = 60, so you pay $60.
Order of operations
Multiplication and division are done before addition and subtraction, as on scientific calculators. For example, 2+3×4 = 14 and 10−6÷2 = 7.
To add first, calculate in two steps: press 2+3 =, then × 4 = to get 20. Or switch to the scientific calculator and use parentheses: (2+3)×4 = 20.
Good to know
- Results show up to 12 significant digits, so 1÷3 = 0.333333333333 and 0.1+0.2 = 0.3.
- Dividing by zero shows “Cannot divide by zero”, and an expression that ends with an operator shows “Incomplete expression”. Your expression is kept so you can fix it with ⌫.
Frequently asked questions
Why is 2+3×4 equal to 14 and not 20?
By the standard order of operations, multiplication comes before addition, so 3×4 is done first. To add first, press 2+3 =, then × 4 = to get 20.
How do I add sales tax to a price?
Enter the price, then + and the tax rate followed by %. For example, $50 with 8% tax is 50+8% = 54.
How do I calculate a discount?
Enter the price, then − and the discount followed by %. For example, 25% off $80 is 80−25% = 60.
How do I calculate a tip?
Enter the bill, then + and the tip percentage followed by %. For example, an 18% tip on $64 gives 64+18% = 75.52 including the tip.
How do I find a percentage of a number?
Multiply by the percentage: 10% of 200 is 200×10% = 20. For more percentage calculations, such as percent change, use the percentage calculator.
Can I use my keyboard?
Yes. Use the number keys, + - * /, %, Enter (equals), Backspace (delete) and Escape (clear).
Is anything I enter saved or sent anywhere?
No. All calculations run in your browser and nothing is sent to a server.