Hand Time ↔ FAT Converter
A hand-held stopwatch always reads faster than fully automatic timing, because of reaction lag at the start and rounding at the finish. NCAA Rule 5-11 and USATF Rule 165 add a fixed offset so hand times can be compared fairly with FAT results.
This offset is a comparison convention set by rule, not a physical correction of the stopwatch reading — it lets a hand time be compared fairly with a FAT result, nothing more.
FAT equivalent
Event: 100m
This offset is a comparison convention set by rule, not a physical correction of the stopwatch reading — it lets a hand time be compared fairly with a FAT result, nothing more.
How the hand time ↔ FAT conversion works
Enter your time and event
Type the time as read off the watch or the results sheet (SS.xx, M:SS or H:MM:SS) and pick the event — the offset depends on the race distance, not just whether it's a sprint.
Choose the direction
Hand → FAT rounds a stopwatch time up to the next tenth, then adds the rule offset. FAT → Hand subtracts the same offset from an electronic time to estimate what a stopwatch would likely have read.
Read the converted time and the rule
The result shows the full breakdown — your input, the rounding step, and the offset applied — plus the NCAA/USATF table so you can check which tier your event falls into.
Why a hand time needs an offset to match FAT
Fully automatic timing (FAT) starts on the gun and stops when the athlete's torso breaks the finish-line beam, to the hundredth of a second. A hand-held stopwatch depends on a timer's reaction: they start it on the gun's flash or sound and stop it when they see the athlete finish, which on average reads faster than FAT because human reaction lag affects the start more than the finish. NCAA Rule 5-11-4 and USATF Rule 165.21 correct for this with a fixed, event-based offset rather than trying to model each timer's reaction individually.
The rule first rounds the hand time UP to the next tenth of a second (a hand watch cannot read hundredths), then adds 0.24 s for races at or under 200m — 60m, 100m, 200m, the 100m/110m hurdles and 4×100m relay — or 0.14 s for races from 300m to 800m — 300m, 400m, the 400m hurdles, 600m, 800m and 4×400m relay. Beyond 800m, national governing bodies apply no conversion: the rounded hand time stands as the official mark. This is a convention for comparing performances across timing methods, not a correction of the stopwatch reading itself.
Hand time to FAT — FAQ
A hand-held stopwatch is started and stopped by a human reacting to the gun and to the finish, so it reads on average faster than fully automatic timing, which starts on the gun and stops on the exact instant the torso crosses the line. NCAA Rule 5-11-4 and USATF Rule 165.21 apply a fixed offset so the two methods can be compared fairly.
First round the hand time UP to the next tenth of a second. Then add 0.24 s for races up to and including 200m (60m, 100m, 200m, 100m/110m hurdles, 4×100m relay), or add 0.14 s for races from 300m to 800m (300m, 400m, 400m hurdles, 600m, 800m, 4×400m relay). No conversion applies beyond 800m.
The offset mainly compensates for reaction lag at the start. Over a longer race, that fixed lag is a smaller fraction of the total time and is partly offset by pacing effects, so rule-makers set a smaller correction for 300m–800m than for races at or under 200m.
Over longer distances, the reaction-time gap between a hand watch and FAT becomes negligible relative to the total race time, so NCAA and USATF do not apply an offset — the hand time, rounded up to the tenth, stands as recorded.
No. It is a fixed convention applied uniformly by rule, not a measurement of any individual timer's reaction. Actual reaction times vary by timer and by race, so a converted mark is an approximation used for record and ranking eligibility, not a precise correction.