All Fermi answers
Fermi #27 · Question 1

How many hockey pucks would it take to cover an NHL ice rink?

Explore the official answer and the simple reasoning behind this Fermi estimate.

1QUESTION 1 OF 3

Answer & explanation

The official answer, with Fermi’s reasoning step by step.

Answer & explanation

Official answer

303,000

pucks

How to estimate it

Fermi’s official “Napkin math”

An NHL rink is 200 feet by 85 feet, so about 17,000 square feet. How many pucks fit in one square foot? A puck is 3 inches across, so four across and four down.

Rink area
~17,000 ft²
Pucks per square foot
4 × 4 = 16
17,000 × 16
≈ 272,000

Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.

Source calculation & reference
NHL rink (200 x 85 ft, 28 ft corner radius)
≈ 16,300 ft² = 2,350,000 in²
Area of one puck (3 in across)
≈ 7.07 in²
Hexagonal packing efficiency
× 0.91
2,350,000 ÷ 7.07 × 0.91
≈ 303,000

Reference cited by Fermi: NHL Official Rules rink specifications (200 x 85 ft surface, 28 ft corner radius; puck 3 in diameter)

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