Calculator
Type a calculation or tap it in on the keypad. The answer updates as you go, and = puts it back in the box so you can keep going.
Answer
414
120 × 3 + 15% =
How to use it
- Type the calculation in the box, or tap it in on the keypad. Commas in numbers like 1,250 are fine.
- Read the answer as you type. The panel also shows the calculation as it was understood and any percentage it worked out.
- Press = or Enter to put the answer back in the box and carry on from it. Earlier answers stay in the tape below the keypad.
- Press C or Escape to start again, or ⌫ to delete the last character.
Worked example
120 × 3 + 15%: the multiplication happens first, 120 × 3 = 360. Then + 15% adds 15% of 360, which is 54, so the answer is 414.
(48 + 12) ÷ 4: the brackets go first, 48 + 12 = 60, then 60 ÷ 4 = 15. Without the brackets, 48 + 12 ÷ 4 is 48 + 3 = 51.
10 ÷ 3 × 3: 10 ÷ 3 is 3.33333333333333333333 to 20 places, and times 3 that’s 9.99999999999999999999, which shows as 10 once it’s rounded to 10 places.
How this is calculated
Multiplication and division happen before addition and subtraction, and powers before both, so 2 + 3 × 4 is 14, not 20. Brackets go first of all. A bracket you leave open at the end closes itself.
The % key works the way it does on a desk calculator. After + or − it takes that percentage of the running total, so 200 + 10% is 220 and 80 − 25% is 60. After × or ÷, or on its own, it just means divide by 100, so 50 × 8% is 4.
The arithmetic is done in exact decimals, not the binary floating point most software uses. Every step keeps 20 decimal places and the answer is shown to 10, with trailing zeros dropped. That's why 0.1 + 0.2 shows as 0.3 here and 0.30000000000000004 in a lot of other places.
Order of operations: brackets, then powers (^), then × and ÷ from left to right, then + and − from left to right.
a + b% = a + a × b ÷ 100, and a − b% = a − a × b ÷ 100
a × b% = a × b ÷ 100, a ÷ b% = a ÷ (b ÷ 100), and b% on its own = b ÷ 100
Each step is kept to 20 decimal places. The answer is rounded half up to 10 places. Numbers up to 999 trillion are supported and powers must be whole numbers up to 1000.
Rates, sources and limits
Last reviewed 23 Sep 2026 by the CalcRabbit team. Estimates only, not financial, tax or medical advice.
Frequently asked questions
How does the % key work?
Like a desk calculator. 200 + 10% adds 10% of 200 and gives 220; 200 − 10% gives 180. That's the quick way to add sales tax or take off a discount. After × or ÷ the % just divides by 100, so 50 × 8% is 4, the tax on a $50 item at 8%. The panel shows the percentage it worked out so you can check it.
Why does 2 + 3 × 4 give 14 and not 20?
This calculator follows the standard order of operations: multiplication and division before addition and subtraction. Some basic pocket calculators work strictly left to right and would give 20. If that's the answer you want, type (2 + 3) × 4.
Why does 0.1 + 0.2 show 0.3 here but 0.30000000000000004 elsewhere?
Most software stores numbers in binary, where 0.1 can't be written exactly, and the tiny error shows up in the last digit. This calculator works in decimal the way you do on paper, so money sums come out to the cent.
Can I use the keyboard?
Yes. Type straight into the box: digits, + - * / ^ % and brackets. Enter works as =, and Escape clears. If nothing on the page has focus, typing a digit or operator goes into the calculator.
Is there a limit to how big a number can be?
Numbers and every step along the way need to stay under 1,000 trillion, and powers must be whole numbers up to 1000. That's far past anything a household budget needs, and it keeps every answer exact.
Can I share a calculation?
Yes. The address in your browser updates as you type, so copying it shares the calculation and its answer.