How does it handle huge exponents without overflowing?

It uses the square-and-multiply method (binary exponentiation), reducing modulo the modulus at every step. The intermediate values never exceed the modulus squared, so even thousand-bit exponents compute quickly and exactly.

What is modular exponentiation used for?

It is the core operation of RSA, Diffie-Hellman and many other public-key cryptography schemes, as well as primality testing and hashing.

Is anything sent to a server?

No — the calculation runs entirely in your browser using arbitrary-precision integers, and nothing is uploaded.

Modular Exponentiation Calculator

Modular exponentiation calculator

Compute (base ^ exponent) mod modulus — the building block of RSA, Diffie-Hellman and other public-key cryptography. The calculator uses the fast square-and-multiply algorithm, reducing modulo the modulus at every step, so it never forms the gigantic full power and handles enormous exponents instantly.

Enter three non-negative whole numbers and the result appears immediately. All arithmetic uses arbitrary-precision integers and runs locally in your browser.