All Fermi answers
Fermi #101 · Question 2

How many bowling pins could you stand upright on one bowling lane, packed side by side as tightly as they fit?

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

2QUESTION 2 OF 3

Answer & explanation

The whole lane, from the foul line to the back of the pin deck.

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

Answer & explanation

Official answer

1,456

pins

How to estimate it

Fermi’s official “Napkin math”

The easiest place to start is the lane, about 60 feet long and 3.5 feet wide. How fat is a pin at its belly? About 5 inches, so maybe 6 pins fit in every square foot.

Lane, 60 × 3.5 ft
≈ 210 sq ft
Pins per square foot
× 6
210 × 6
≈ 1,260 pins

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

Source calculation & reference
Lane, foul line to back of pin deck (USBC)
62 ft 10 in × 41.5 in
Pin at its widest (USBC)
4.766 in, so 8 across
Rows nested into the gaps, every 4.13 in
182 rows
182 rows × 8 pins
1,456 pins

Reference cited by Fermi: USBC Equipment Specifications Manual: lane length and width, pin diameter

How close was your guess?

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Compare by ratio: divide the larger number by the smaller one. The closer to 1×, the better.

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