Big Number Calculator
Add, subtract, multiply, divide and power huge whole numbers with unlimited precision.
What is a big number calculator?
Ordinary calculators lose accuracy once numbers pass about 15–16 digits, rounding the rest away. A big number calculator works with arbitrary-precision integers, so every digit of the answer is exact — no matter how long. This version uses your browser's built-in BigInt support and never rounds.
What it can do
You can add, subtract, multiply and divide (getting both the quotient and remainder), take the modulo, raise a number to a power, find the greatest common divisor of two numbers, and compute a factorial. Results are shown in full, along with a count of how many digits they contain.
How to use this calculator
Type your first number, choose an operation, and enter the second number where required (the factorial uses only the first). Spaces and commas in your input are ignored, so you can paste grouped numbers. Press Calculate to see the exact result.
Where big numbers matter
Arbitrary-precision arithmetic is essential in cryptography, where keys are hundreds of digits long, as well as in combinatorics, number theory and scientific computing. Because these values overflow normal number types, a dedicated big number tool is the reliable way to keep every digit correct.
Frequently Asked Questions
What is the Big Number Calculator?
Add, subtract, multiply, divide and power huge whole numbers with unlimited precision. It runs instantly in your browser and is completely free to use.
What do I need to enter to use the Big Number Calculator?
The Big Number Calculator is an interactive tool: type directly into it and the result updates as you go. Everything runs on your own device, so nothing you enter is sent to a server.
How accurate is the Big Number Calculator?
The Big Number Calculator uses standard, widely-accepted formulas, so its figures are reliable estimates for everyday planning. They are not a substitute for advice from a qualified professional.
Is the Big Number Calculator free, and do I need an account?
Yes. The Big Number Calculator — and every other calculator on Calculatis — is completely free, with no registration, no download and no limit on how often you use it.