Big Number Calculator
Arbitrary-precision integer and decimal calculator: add, sub, mul, div, mod, pow, gcd, lcm, factorial.
Overview
The Big Number Calculator handles integer and decimal arithmetic with arbitrary precision — no silent overflow when you compute 100! or 2^1000. Standard operations like add, subtract, multiply, divide, modulo, power, gcd, lcm and factorial are all supported and return exact results.
It is ideal for cryptography hobbyists experimenting with RSA-sized primes, students computing exact combinatorial counts, scientists juggling numbers outside double-precision range and anyone tired of 1e308 rounding their answers into nonsense.
How it works
Unlike floating-point, arbitrary-precision arithmetic stores numbers as variable-length integer arrays. Add and subtract run digit-by-digit with carry / borrow. Multiplication uses schoolbook for small operands and Karatsuba or Toom-Cook style algorithms once the numbers get large.
Division produces an exact quotient and remainder for integers; for decimals it returns enough digits to be useful, falling back to a fraction when the result is irrational or repeats. Factorials, gcd (Euclidean algorithm) and lcm (a * b / gcd) are exact and only limited by available memory.
Examples
100! → 93326215443944152681699238856266700490715968264381621
46859296389521759999322991560894146397615651828625369
7920827223758251185210916864000000000000000000000000
2^256 → 115792089237316195423570985008687907853269984665640
564039457584007913129639936
gcd(12345678901234567890, 98765432109876543210)
→ 900000000900000000090
1 / 7 → 0.142857142857... (repeating)
FAQ
Is there an upper limit?
In practice, yes — operations get slow on very large inputs. A million-digit factorial is doable but takes time. Hundreds of digits run instantly.
Are results exact?
For integers, yes. For division of two integers the result is exact if it terminates, otherwise the tool reports the repeating pattern or a fraction.
Does it support negative numbers?
Yes for all integer operations. Factorial requires a non-negative integer; power supports negative exponents with rational results.
How does it differ from a scientific calculator?
A scientific calculator uses 64-bit floats which run out of precision around 17 digits. This tool keeps every digit.
Can I use scientific notation for input?
Yes — 1e50 is accepted and treated as the integer 10^50.