Open Water Swim Time Calculator

Estimates open-water swim finish time from distance and pace.

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Enter details

Distance(m)

Pace per 100 m

Result

Fill in the fields to see your result.

Estimate only — real results depend on terrain, weather, fatigue, conditions and individual fitness. Not medical or coaching advice.

Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.

How to use this calculator

Enter the distance (m) and your expected open-water pace per 100 m.
Read the estimated time.

How it works

Time = (distance ÷ 100) × pace per 100 m. Use a realistic open-water pace, not your pool pace.

Worked example

1900 m @ 2:00/100 m. = 38:00.

Common mistakes

Using your pool pace unchanged — open water is typically 5–15% slower from sighting, chop and no walls.
Forgetting current and wetsuit effects, which can swing the time either way.

Tips

Times are estimates only — not medical or coaching advice. Always train safely and follow event rules.
Distances are editable: choose “Custom…” to enter your own course lengths.

Frequently asked questions

Why is open water slower than the pool?

No walls to push off, sighting that breaks your stroke, plus chop and currents all add time — usually 5–15% over the same distance.

Does a wetsuit make me faster?

Usually yes — extra buoyancy lifts your legs and reduces drag, often saving several seconds per 100 m in cool water.

Why is open water slower?

Chop, sighting, current, temperature and wetsuit drag all add time versus a pool.

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Cite this tool

Zerdly. (2026). Open Water Swim Time Calculator. Retrieved from https://www.zerdly.com/tools/open-water-swim-time-calculator/

Tip: Enter any known values to calculate the remaining results.

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