Swim Time Calculator

Enter a target pace and a distance, and this calculator returns your projected finish time, average 50 and 100 splits, speed, and (optionally) the number of pool lengths.

Inputs
Common distances
Finish time
25:00
Average 50 m split
0:50
Average 100 m split
1:40
Speed (mph)
2.24
Speed (km/h)
3.60

Formula

The calculator converts your pace into seconds per meter, then multiplies by the total distance in meters:

finish time = (distance in meters) × (pace seconds ÷ basis distance in meters)

When you pick a yard-based basis or yard distance, the value is first converted using 1 yard = 0.9144 meters, so meter and yard inputs compose correctly.

Example 1 — Ironman swim

Pace 1:45 per 100 m for 3800 m: 3800 × (105 ÷ 100) = 3,990 seconds ≈ 1:06:30.

Example 2 — 500 yard test

Pace 1:30 per 100 yd for 500 yd: 500 × (90 ÷ 100) = 450 seconds = 7:30.

FAQ

Should I use per-50 or per-100 pace?

Whatever your workouts use. Short-course sets are often tracked per 50, while distance training is more often tracked per 100.

Does the calculator account for wall push-offs or dives?

No. It assumes a constant pace over the entire distance. Actual finish times in a pool are usually a bit faster than a flat calculation because of turns; in open water they are usually a bit slower.

Why does the pool-length count sometimes end in a fraction?

Because 1 yard ≠ 1 meter. A 1500 m swim is about 65.6 lengths of a 25 yard pool. Round up in practice.

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