Swim Pacing Calculator

Split per 100m is set directly from the target pace you enter -- it's simply that value passed through, since "pace per 100m" is a rate, not a total. Race distance determines how many 100m splits the race contains and therefore the total race time, but it doesn't change the per-100m pace figure itself, which stays whatever you input regardless of how long the race is.

A negative split means swimming the second half of a race faster than the first, which this calculator suggests by pacing the first half about 1.5% slower than your target and the second half about 1.5% faster. Starting conservatively preserves energy for a stronger finish, which many swimmers find produces a better overall time than starting fast and fading in the final stretch.

Total race time takes your target pace per 100m, converts it to a per-meter rate by dividing by 100, and multiplies that by the full race distance in meters. Raising either your target pace (a slower pace, more seconds per 100m) or the race distance increases total race time, since both directly scale how long the swim takes.

Yes -- the calculator works the same way regardless of venue since it only needs a target pace and a total distance, not a specific pool length. Enter your target pace per 100m and the open-water distance (750m, 1500m, 1900m, or 3800m are common), and the split table and negative-split pacing apply exactly as they would for a pool swim, though real open-water pacing is harder to hold precisely without wall push-offs to reset your rhythm.