Power Modulo Calculator

Use our power modulo calculator (power mod calculator) to compute x^y mod n quickly. Includes what does modulo mean, how does modulo work, modulo examples, and the power modulo method used in modular arithmetic.

x (base)
Enter a whole number (negative allowed).
y (exponent)
Enter a whole number (0 or higher).
n (divisor)
Enter a whole number greater than 0.
Results
Power modulo
Computed as (x^y) mod n using fast modular exponentiation.
xy mod n = ?
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What Does Modulo Mean?

Modulo is an operation that returns the remainder after division. For example, 17 mod 5 = 2 because 17 ÷ 5 leaves a remainder of 2.

If you’re asking what does modulo mean or how does modulo work, it’s basically “what’s left over after dividing.”

Power modulo (also called modular exponentiation) is when you compute a power and then take the result modulo n, like x^y mod n. This shows up in number theory and many practical computing tasks.

Power Modulo Formula

Power modulo is the remainder when x^y is divided by n. In practice, modular exponentiation is used to keep numbers manageable.

Power modulo =
r = x^y mod n

r is the remainder after dividing x^y by n.

Helpful modular rule =
(a · b) mod n = ((a mod n) · (b mod n)) mod n

This lets you reduce intermediate values when computing large powers.

x
= Base
y
= Exponent
n
= Modulus (divisor)
r
= Power modulo result (remainder)
Modulo example
17 mod 5 = 2

17 divided by 5 leaves remainder 2.

Power modulo example
3^4 mod 5 = 81 mod 5 = 1

Compute the power, then take the remainder.

How to Use the Power Modulo Calculator

  1. 1

    Enter the base x.

  2. 2

    Enter the exponent y.

  3. 3

    Enter the modulus n.

  4. 4

    The calculator returns r = x^y mod n (the remainder).

Frequently Asked Questions

What does modulo mean?

Modulo means the remainder after division. a mod n is the remainder when a is divided by n.

How does modulo work?

Divide a by n and take the remainder. Example: 14 mod 4 = 2 because 14 = 3·4 + 2.

What are some modulo examples?

10 mod 3 = 1, 20 mod 5 = 0, and 7 mod 2 = 1.

What is power modulo / power mod?

Power modulo is computing x^y mod n, the remainder when x raised to the power y is divided by n.

Why use a power modulo calculator?

Because x^y can become extremely large. Modular exponentiation techniques compute the same remainder efficiently without storing huge numbers.

Is power modulo the same as (x mod n)^y?

You can reduce x first: (x mod n)^y mod n gives the same result as x^y mod n, but you still apply mod n at the end.