Counting, Permutations & Combinations

Pigeonhole Principle Calculator

Find a guaranteed occupancy or the minimum objects needed to force one.

Counting & Combinatorics

Apply the generalized pigeonhole principle

Guaranteed minimum

At least one box contains

Enter valid values to see the result.

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Quick guide

How to use this calculator

  1. Choose the question you need answered.
  2. Enter the number of boxes and either objects or target occupancy.
  3. Read the guaranteed minimum.

Calculation method

Use the generalized pigeonhole bound

Distributing n objects among k boxes guarantees one box contains at least ceiling(n/k). To guarantee at least m objects in one box, k(m−1)+1 objects are sufficient and necessary.

Worked example

Thirteen objects in four boxes

At least one box must contain four objects.

⌈13/4⌉ = 4

Supported inputs

Precision and limits

Discrete domain

Inputs are whole counts. Negative, fractional, grouped, and scientific-notation inputs are rejected.

Exact integers

Results use arbitrary-precision integers and are never rounded. Inputs and output size are bounded to keep the page responsive.