Calculate average swimming speed, pace per 100 meters, equivalent pool lengths, and constant-pace projected times.
Keep the pool and timing basis together
Record whether the distance is a measured length, a lap count translated into distance, or another source. Confirm the pool-length unit before interpreting equivalent lengths. Compare speed with pace over the same timed interval. Projected times extend that average pace; they do not account for different turns, stops, fatigue, or conditions over a new distance.
Inputs and method
Enter swim distance and elapsed seconds. Average speed is converted to meters per second and pace is 100 meters divided by that speed; pool length is used to report equivalent lengths, which may be fractional.
Interpreting the estimate
Use the result as a planning value and keep input precision consistent with the measurements or source data you have. Small displayed differences can come from final-place rounding; intermediate values are not rounded.
Assumptions and limits
Starts, turns, rests, pool measurement, and timing method are included only insofar as they are present in the elapsed time. The calculator does not assign a performance level.
Empty entries, invalid numbers, prohibited negatives, zero denominators, impossible relationships, and unsupported options trigger a validation message instead of a misleading result.
Method basis
Speed, pace, equivalent lengths, and projections are publisher derivations from entered distance and elapsed time. Projections assume the same average pace and do not adjust for stroke. For related pace tools, see the running pace calculator, the pace converter calculator, and the speed converter.