What open water costs you
A lake or sea swim has no walls to push off, no lane rope to follow and no clear water. Sighting every 8–10 strokes adds distance and breaks rhythm. The usual penalty is 3–8 seconds per 100 m compared with the same effort in a pool, and more if there is chop or a strong current. Lakeswim pace is therefore its own number, not a pool pace with a rounding error attached.
Wetsuits and currents
A wetsuit improves buoyancy and typically saves 3–6 seconds per 100 m for age-group swimmers. A current can do more than that in either direction — a down-current swim can produce times that look impossible, and an up-current leg can destroy a race. Course measurement also varies: a 1900 m race is rarely exactly 1900 m.
Using the numbers
The result shows your pace and a pool-equivalent estimate, which is useful for setting expectations before a race. If your pool pace is 1:50 and your open water pace is 1:58, the gap is normal. If it is 2:15, sighting or anxiety is probably costing more than the water itself.
Frequently Asked Questions
Why is my open water pace slower?
No turns, sighting, chop, and swimming in a crowd. All four add time; none of them mean you are less fit.
How often should I sight?
Every 8–12 strokes in clear water, more often in a crowd. Lift your eyes without lifting your whole head.
Does a wetsuit really help?
Yes, for most age-group swimmers — buoyancy raises the legs and reduces drag. Strong swimmers gain less.
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Privacy & your data
SwimRunPace calculates everything in your browser. Distances, times and body weights are never uploaded — there is no account, no server-side record and no training history stored between visits.