About the big number calculator
The big number calculator performs exact arithmetic on numbers with hundreds of digits: addition, subtraction, multiplication, division, powers, square roots, factorials, remainders and the greatest common divisor and least common multiple of whole numbers. Where a standard calculator would switch to scientific notation and lose digits, this one returns every digit.
For division and square roots you choose how many significant digits to keep.
Who should use the big number calculator
- Students exploring factorials, powers and large primes.
- Programmers checking arbitrary-precision results.
- Puzzle solvers and number theory enthusiasts.
How to use the big number calculator: what each input means
- Operation
- Add, subtract, multiply, divide, power, square root, factorial, remainder, GCD or LCM.
- Numbers
- Up to 1,000 digits each. Spaces and commas are ignored. Factorial, remainder, GCD and LCM need whole numbers.
- Factorial
- A whole number from 0 to 3,000 (3,000! has 9,131 digits).
- Exponent
- A whole number from 0 to 5,000 for powers.
- Significant digits
- For division and roots, between 5 and 500.
How the big number calculator works: method and formula
Numbers are stored as exact integers scaled by a power of ten. Addition, subtraction, multiplication, whole-number powers, factorials, remainders, GCD and LCM are exact. Division and square roots are computed to the chosen number of significant digits and rounded.
- Exact product
- a × b with all digits kept
How to read your big number calculator result
The result panel shows the headline and the full number in a scrollable block, with digit counts. When both numbers are whole, division also reports the integer quotient and remainder.
Big Number Calculator worked example
Multiply 123456789012345678901234567890 by 987654321098765432109876543210.
- Both numbers have 30 digits.
- The exact product has 60 digits.
121,932,631,137,021,795,226,185,032,733,622,923,332,237,463,801,111,263,526,900
Practical uses of the big number calculator
- Checking factorials, remainders and large powers.
- Verifying results from programming languages with limited precision.
- Exploring number patterns.
Assumptions and limitations of this calculator
- Inputs are limited to 1,000 digits and results to 20,000 digits.
- Division and roots are rounded to your chosen significant digits.
- Very large calculations are limited by browser performance.