Skip to main content

How to Calculate Modular Arithmetic

What is Modular Arithmetic?

Modular arithmetic wraps numbers around after reaching a modulus. a mod m is the remainder when a is divided by m. Foundational in cryptography, checksums, and number theory.

Step-by-Step Guide

  1. 1a mod m = remainder of a ÷ m
  2. 2(a+b) mod m = ((a mod m)+(b mod m)) mod m
  3. 3Modular exponentiation: fast algorithm for aⁿ mod m

Worked Examples

Input
17 mod 5
Result
2
17 = 3×5 + 2

Ready to calculate? Try the free Modular Arithmetic Calculator

Try it yourself →

Settings

PrivacyTermsAbout© 2026 PrimeCalcPro