This form allows a runner to use a race performance to predict times for other distances. The calculation rule is a five-percent slowdown for each doubling of distance. Enter DISTANCE as a number and units, for example 10 miles, 5k, 1/2 marathon. Enter TIME as numbers with colons between hours, minutes, and seconds, for example 1:08, 19:30, 85:32. The output will have standard distances (mile, 5K, 10K, half-marathon, and marathon) and you can add other distances by entering them in the left column.