About the Big Number Calculator
A normal calculator, spreadsheet or phone app keeps only about 15 significant digits, then rounds and switches to scientific notation. This big number calculator keeps every digit of whole numbers up to 2,000 digits long. You can add, subtract, multiply, divide with remainder, take a remainder, raise to a power or find the greatest common divisor and least common multiple. It is useful for number theory, programming checks, cryptography exercises, factorial and power puzzles, and anyone who needs an exact answer rather than an approximation.
Updated October 2026
How to use the Big Number Calculator
- 1Paste or type the first whole number into box A.
- 2Choose the operation you want.
- 3Paste or type the second whole number into box B.
- 4Read the exact answer, which scrolls inside the result box if it is long.
- 5Use the Copy result button to take the full number to another document.
When you need exact big-number maths
Exact large integers show up more often than you might think. Programmers check overflow in 64-bit variables, which top out near 9.2 quintillion. Maths students compute factorials, Fibonacci terms and powers of two and three. Cryptography courses use modular arithmetic with numbers hundreds of digits long. Puzzle solvers work out how many ways something can happen. In all of these, one lost digit makes the whole answer wrong.
Useful examples to try
- 2 to the power of 100 is 1,267,650,600,228,229,401,496,703,205,376.
- Multiply two 30-digit numbers and see all 60 digits of the product.
- 100 divided by 7 gives 14 with a remainder of 2.
- The GCD of 12 and 18 is 6, and their LCM is 36.
Tips for pasted numbers
Numbers copied from a document often contain commas, spaces or line breaks. All of these are removed automatically, so a value written as 1,234,567 works as it is. Letters, decimal points and scientific notation are not accepted and give a clear message. If you need a factorial or Fibonacci number specifically, the Factorial Calculator and Fibonacci Calculator are built for those, and the Long Division Calculator shows the written steps for division. The Number Base Converter handles binary and hexadecimal.
Features
- Whole numbers of up to 2,000 digits
- Add, subtract, multiply and divide with remainder
- Remainder, power, GCD and LCM
- Every digit exact, never rounded
- Digit count and comma-grouped version
- Commas and spaces in pasted numbers are ignored
- Calculated in your browser
Frequently asked questions
Why does my normal calculator give the wrong answer for big numbers?
Most calculators and spreadsheets store numbers as floating-point values with about 15 to 17 significant digits. Beyond that, the lower digits are lost. For example, 2 to the power of 100 is 1267650600228229401496703205376, but a spreadsheet shows 1.26765E+30. This tool uses arbitrary-size integers, so none of the digits are lost.
How big a number can I use?
Each input can have up to 2,000 digits. Powers are limited so the answer stays within about 6,000 digits, and exponents above 100,000 are refused. That keeps the page fast on a phone while still covering nearly every practical use.
Can I use decimals or negative numbers?
Negative whole numbers work, with a minus sign in front. Decimals do not, because this tool is exact integer arithmetic. For decimal work with ordinary-sized values use the Online Calculator or the Rounding Calculator.
What is the difference between divide and remainder?
Divide gives the whole-number quotient and also shows the remainder. The remainder operation gives only the remainder, always as a non-negative number for the modulo form, with the sign-preserving version shown beneath it. Use whichever your task defines.
What does the greatest common divisor do?
The greatest common divisor, or GCD, is the largest whole number that divides both inputs exactly. The tool also shows their least common multiple. These are used for simplifying fractions and in number theory and cryptography.
Is my number sent anywhere?
No. The calculation runs entirely inside your browser, so numbers you type or paste, including values from coding exercises or private keys you are studying, never leave your device.