Big Number Calculator
Do exact arithmetic on huge whole numbers — add, subtract, multiply, divide, mod, power and GCD with full BigInt precision, no rounding.
Big integer arithmetic
How to use this calculator
1. Enter two whole numbers
Type integers of any length into A and B. There is no digit limit for addition, subtraction and multiplication — paste 100-digit numbers if you like.
2. Pick the operation
Choose add, subtract, multiply, divide, mod, power or GCD. Division shows both the whole-number quotient and the remainder, since BigInt has no fractions.
3. Watch the power guard
Powers grow explosively, so an exponent above 100,000 or a result that would be astronomically long is refused with a warning rather than freezing your browser.
4. Copy the exact answer
The full-precision result is displayed as text — select and copy it. Every digit is exact because the math runs on BigInt, not floating point.
About big number arithmetic
Why do normal calculators lose precision?
JavaScript numbers are 64-bit floating point and only store integers exactly up to 2⁵³ (about 9 quadrillion). Past that, digits are rounded. BigInt represents whole numbers of any size exactly, so this tool keeps every digit.
Integers only
BigInt works with whole numbers, so this calculator does not handle decimals. Division returns a quotient and a remainder instead of a fractional result. For decimals, use a standard arithmetic calculator.
How is GCD computed?
The greatest common divisor uses the Euclidean algorithm, repeatedly replacing the larger value with the remainder of dividing the two, until one becomes zero. It is fast even for enormous numbers.