The arithmetic
Convert the elapsed time to seconds. Divide that value by the distance, then multiply by 100 for the average per 100 units, or by 50 for the average per 50 units. The unit stays the same as the input: meters remain meters and yards remain yards.
For example, 200 meters in 2 minutes 40 seconds is 160 seconds total. The average per 100 meters is 160 ÷ 200 × 100 = 80 seconds, displayed as 1:20.00. The average per 50 meters is 40 seconds.
Worked examples
| Completed swim | Elapsed time | Average per 100 | Average per 50 |
|---|---|---|---|
| 200 m | 2:40.00 | 1:20.00 / 100 m | 0:40.00 / 50 m |
| 400 m | 6:00.00 | 1:30.00 / 100 m | 0:45.00 / 50 m |
| 500 yd | 7:30.00 | 1:30.00 / 100 yd | 0:45.00 / 50 yd |
What the result does not tell you
An average does not show how the individual lengths were paced. It does not account for a change in stroke, the starting method, turns or rest included in the entered time. If you include pauses, the result includes them too.
The calculation does not convert a performance between pool courses, predict a race result or prescribe a workout. For swims shorter than the displayed reference distance, the value is a normalized average rather than a prediction that the pace can be sustained.
Keep a useful record
Save the event, course, distance, elapsed time and timing context together in your own log. If you want to discuss the result with a coach, those details are more useful than a pace number alone. Read the training-log guide for a simple structure.
Same unit in, same unit out. A 100-yard pace is not a 100-meter pace. Use the glossary to distinguish SCY, SCM and LCM.