Prior to the early 1980s, all running events were run in yards. Since running event records exist in both meters and yards it is necessary to convert these earlier performances.

The basic procedure is that of interpolation, taking the following steps (I've also given an example below):

1. Convert the time into seconds (if appropriate).

2. Divide the time by a yard conversion factor (see table below).

3. Multiply the result from 2 (above) by the race distance, in meters.

4. Convert the time into minutes and seconds (if appropriate).

Example
Suppose a person runs the 100 yard dash in 12.1 seconds. Since the time is only in seconds, we can skip step one above. The yard conversion factor from the table below is 91.44. Dividing 12.1 by 91.44, we obtain an answer of 0.1323272. Multiplying this answer by the race distance of 100 meters, and then rounding to the nearest tenth of a second, the final time becomes 13.2. Running a 100 yard dash in 12.1 is equivalent to running a 100 meter dash in 13.2.

Calculating the yard conversion factor
The yard conversion factor is simply the result of converting the distance in yards into its equivalent distance in meters. For example, take the distance of 100 yards. 100 yards is the same as 300 feet, which is the same as 3600 inches. Since 1 inch equals .0254 meters, 3600 inches equals 91.44 meters. That is, 100 yards is equal to 91.44 meters (making 91.44 the conversion factor for 100 yards).

The table below lists the yard conversion factors for each race.

Yard distance	Conversion factor (equivalent meter distance)
100 yards	91.44 meters
110 yards	100.584 meters
220 yards	201.168 meters
330 yards	301.752 meters
440 yards	402.336 meters
880 yards	804.672 meters
1760 yards (1 mile)	1609.344 meters
3520 yards (2 mile)	3218.688 meters