Pigeonhole Principle Calculator

Explore guaranteed repetition, occupancy limits, and contradiction checks. Compare pigeons, holes, targets, and impossible arrangements. Build stronger proofs using quick results, tables, and exports.

Advanced counting, collision, and proof support

Calculator Inputs

Choose a mode, enter whole numbers, and submit to see the result above this form.

Switch between proof, design, and feasibility tasks.
Use the number of objects being distributed.
Use the number of categories or containers.
For example, set 3 to test “at least 3”.
Used by contradiction mode to test a claim.

Formula Used

1) Guaranteed minimum occupancy

Guaranteed load = ceil(P / H), where P is pigeons and H is holes. This guarantees at least one hole reaches that value.

2) Force a target occupancy

To guarantee at least k pigeons in one hole, the minimum required count is H × (k - 1) + 1.

3) Maximum safe pigeons without forcing k

Maximum safe pigeons = H × (k - 1). One more pigeon forces some hole to contain at least k.

4) Minimum holes needed

Minimum holes = ceil(P / (k - 1)). This keeps every hole below k, if enough holes are available.

How to Use This Calculator

  1. Choose the calculation mode matching your proof or design problem.
  2. Enter the number of pigeons, holes, and target occupancy when needed.
  3. Use contradiction mode when testing whether a claimed upper limit is possible.
  4. Press Calculate Result to show the answer below the header.
  5. Review the interpretation bullets to understand the proof logic.
  6. Use the export buttons to save the result as CSV or PDF.

Example Data Table

Mode Pigeons Holes Target / Cap Output
Guaranteed minimum occupancy 17 5 4 At least one hole has 4 pigeons.
Maximum safe without target collision 6 Target 3 Maximum safe pigeons = 12.
Minimum holes needed 25 Target 5 Minimum holes required = 7.
Contradiction checker 22 4 Cap 5 Impossible, because capacity is only 20.

Frequently Asked Questions

1) What does this calculator prove?

It shows guaranteed repetition or crowding when objects are distributed into limited categories. It also checks thresholds, safe limits, required holes, and contradiction-style claims.

2) Why must all inputs be whole numbers?

The pigeonhole principle counts discrete objects and containers. Fractional pigeons or fractional holes do not fit the combinatorial meaning of the theorem.

3) What is guaranteed minimum occupancy?

It is the least number that some hole must reach, no matter how evenly the pigeons are distributed. The calculator finds it using the ceiling of pigeons divided by holes.

4) How does the target occupancy option work?

It tests when at least k pigeons must appear in one hole. The forcing threshold is one more than the largest arrangement that still keeps every hole below k.

5) What is contradiction mode useful for?

Use it when someone claims no hole exceeds a chosen cap. The calculator compares total capacity under that claim against the actual pigeon count.

6) Can this help with proofs and olympiad questions?

Yes. It gives fast bounds, forcing thresholds, and contradiction checks that often form the key step in contest proofs, counting arguments, and discrete mathematics exercises.

7) Why does one extra pigeon matter so much?

Because the safe arrangement already fills every hole to the maximum allowed level. The next pigeon has nowhere safe to go, so the target occupancy becomes unavoidable.

8) What do the CSV and PDF exports include?

They export the computed result metrics for the submitted case. This helps you save worked examples, attach notes, or share proof-supporting calculations.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.