How are races timed, and how exact are the times?
B · Beginner · Running and finishing · 6 of 7Times are official when taken by a fully automatic system started by the gun and read from the photo finish image. Sprint times are recorded to a hundredth of a second, always rounded up. Hand timing is still valid and is recorded to a tenth.
How it works
- Three methods: hand timing, fully automatic timing from a photo finish system, and transponder timing for races outside the stadium.
- When the clock stops: when any part of the athlete's torso reaches the plane of the near edge of the finish line.
- Automatic start: the system is started by the starter's signal, with a delay of no more than 0.001 second.
- Rounding: for track races up to and including 10,000 m, a time that is not an exact hundredth is recorded "to the next longer 0.01 second". The rule's example is 26:17.533, recorded as 26:17.54.
- Official: photo finish times are official unless the official in charge decides they must be wrong.
- Hand timing: three timekeepers time the winner, starting their watches from the flash or smoke of the gun.
- Hand rounding: a hand time that is not an exact tenth is recorded to the next longer 0.1 second, so 10.11 becomes 10.2.
- When watches disagree: if two of three agree, that is the time. If all three differ, the middle one is official.
- Lap times: recorded in races of 800 m and over wherever possible.
- Reaction times: where the blocks are linked to a start information system, each athlete's reaction time is measured and shown in the results.
Tricky cases
A photo finish shows 9.991 seconds. What time is recorded?
10.00. A time that is not an exact hundredth goes up to the next longer hundredth.
Two athletes are both given 10.05. Did they tie?
No, not necessarily. Placings are read from the image, which can separate athletes whose recorded times are the same.
Is a hand-timed result valid?
Yes. Hand timing is one of the three official methods.
The automatic timing fails during a race. Is there no time?
No, there is one. Back-up timekeepers take hand times, which become official.
Why the rule exists
A person pressing a button adds a reaction delay at both ends of the race, which is why hand times are recorded more coarsely. Rounding up means no athlete is ever credited with a time faster than they ran.
Where it differs
| Where | What changes | Source |
|---|---|---|
| World Athletics rules | As above | TR 19 |
| Track races longer than 10,000 m | Recorded to the next longer 0.1 second | TR 19.23.2 |
| Races outside the stadium | Recorded to the next longer whole second | TR 19.23.3 |
| A system not started by the gun | Its times count as hand times | TR 19.17 |
From the rule book
World Athletics, Competition and Technical Rules, 2026 Edition, Technical Rule 19. Checked 14 October 2026. Official document: World Athletics Competition and Technical Rules 2026 (PDF).