Hand timing to FAT converter

A timekeeper starts the watch when they see the flash or smoke of the gun, so a hand time misses part of the reaction delay that fully automatic timing captures from the gun itself. That makes hand times faster than FAT times for the same run. World Athletics corrects for this with fixed amounts, listed in the introduction to its Scoring Tables of Athletics:

The Combined Events tables use the same factors and add nothing for races over 400m. Before converting, a hand time has to be recorded properly. Under World Athletics Technical Rule 19, hand times on the track are rounded up to the next tenth (a watch reading of 10.11 is recorded as 10.2), and FAT times are rounded up to the next hundredth. The calculator applies the same rounding.

A 100m hand time of 10.6 converts to 10.6 + 0.24 = 10.84 FAT. A watch reading of 10.63 is first recorded as 10.7, so it converts to 10.94.