Sprints
Hand time to FAT converter
Turn a stopwatch time into an estimated fully automatic (FAT) time, or the other way round. Three conventions are in use, and the converter shows what each one adds.
Why hand times are faster
A hand timer starts the watch when they see the flash or smoke of the gun. That reaction takes time, so the watch starts after the race has begun. At the finish, timers watch the runner come in and tend to stop the watch a little early. Both errors make the time shorter.
FAT starts from the signal of the gun itself and reads the finish from a photo, so it has neither error. The 0.24 s figure comes from a study of expert timers at the 1972 Munich Olympics. Both figures held up in an informal check at the 1976 US Olympic Trials. Less experienced timers can be further off: in Track & Field News comparisons, high school timers were off by 0.40 to 0.45 s on average.
How it is calculated
- Round the hand time up to the next tenth. Hand times are recorded in tenths and always rounded up: a watch reading of 10.83 is 10.9.
- Add the figure for the convention and the race distance.
Going from FAT to hand, the figure is taken off and the result is rounded up to the tenth, the way a hand time would be recorded. The three conventions add these amounts:
| Convention | Under 300 m | 300 m | 400 m | 500–600 m | 800 m and up |
|---|---|---|---|---|---|
| Statistics (T&F News, Athletic.net) | 0.24 s | 0.14 s | 0.14 s | 0.14 s | none |
| Combined events (USATF, WMA) | 0.24 s | 0.24 s | 0.14 s | none | none |
| US high school (NFHS) | 0.24 s | 0.24 s | 0.24 s | 0.24 s | 0.24 s |
Track & Field News and Athletic.net rankings use the statistics convention. Combined events add the correction to a hand time before it is scored. NFHS publishes one figure, 0.24 s, for every race.
Worked example
A 100 m timed at 10.83 on a stopwatch is recorded as 10.9. Adding 0.24 s gives an estimated FAT time of 11.14. A hand-timed 400 m in 48.2 is an estimated 48.34 with the statistics or combined events convention, and 48.44 with the NFHS figure.
Limits
- The figures are averages from good timers. Any one race can be off by more, and inexperienced timers by much more.
- A converted time is an estimate for comparing marks. It is not valid for records, for rankings that require FAT, or for qualifying marks. Records and qualifying marks in sprint events need fully automatic timing.
- From 800 m up, most conventions add nothing: the rounding is the whole difference.
Sources
NFHS, “Converting Times: Manual to FAT” (2014). Athletic.net, “Hand Time Conversion Standards”, following Track & Field News. USATF combined events scoring calculator. World Masters Athletics, 2023 rules, Appendix B (combined events). World Athletics Technical Rule 19.10.1 (hand times recorded to the next longer tenth). Track & Field News, “Hand-Timing Myth? Hollobaugh Hammers A Final Nail” (2026).
Questions
How much do you add to a hand time?
Most often 0.24 seconds for races under 300 m and 0.14 seconds from 300 m up to 800 m, after rounding the hand time up to the tenth. US high school (NFHS) rules add 0.24 seconds at every distance.
Why are hand times faster than FAT?
The timer reacts late to the gun, so the watch starts after the race has begun. At the finish, timers tend to stop the watch early as the runner arrives. Both make the hand time shorter.
Is a converted time valid for records?
No. A converted time is an estimate for comparing marks. Records and qualifying marks in sprint events need fully automatic timing.
Why does 10.83 become 10.9?
Hand times are recorded to the tenth of a second and always rounded up. A watch reading of 10.83 is recorded as 10.9 before any conversion.
Log races with the time you ran.
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