What was Usain Bolt’s top speed, in miles per hour?

How to get close to this number

The arithmetic is right there in the race. A hundred metres in a bit under ten seconds is an average you can compute in your head, and a sprinter's peak is meaningfully faster than their average because the first seconds are spent accelerating from a standstill. Work out the average, then add a margin for the fact that the start drags it down, and you are very close.

The trap is the word "top". Casual guesses often quote the race average and stop there, which undershoots. Bolt's peak came in the middle of the run, after acceleration was complete and before deceleration set in — the explanation above places it between the sixty and eighty metre marks. Every sprinter is slowing down by the finish line; the winner is the one slowing down least.

It is also worth being clear that this is an instantaneous speed derived from high-frequency timing of a single race, not a record in its own right. World Athletics ratifies times, not speeds, so the peak figure comes from biomechanical analysis rather than from the results sheet. That is why it is quoted with the championship and year attached, and why different analyses of the same run can differ in the final decimal.