Swim Pace Calculator

Solve Pace, Time, or Distance — Whichever One You're Missing

Swim training math usually comes down to one of three questions: how fast was that pace, how long will this set take, or how far did I actually swim. This calculator handles all three from the same set of fields — pick which one you're solving for, fill in the other two, and it works out the rest along with a per-length split breakdown, a SWOLF efficiency score if you track stroke count, and predicted times across the standard race distances.

How to use it

• Choose what you're solving for: pace per 100, total time, or total distance.
• Fill in the two fields that remain — for example, if you're solving for pace, enter your total distance and total time.
• Set your pool length (25 or 50) to get an accurate per-length split time and lap count.
• Optionally fill in the SWOLF section with your time and stroke count for one length to get an efficiency score — lower is better.

Real-world use cases

Working out your pace per 100m after finishing a set so you can log it in a training plan, figuring out how long a planned 2000m swim will take at your current pace before you get in the pool, checking how far you actually swam if you know your time and roughly how fast you were going, or tracking whether your SWOLF score is improving over a training block as a sign your stroke efficiency is getting better.

Frequently asked questions

What exactly is SWOLF and why would I track it?

SWOLF (a blend of "swim" and "golf") adds your time in seconds for one pool length to the number of strokes it took to swim it — like golf, a lower score is better. It's a simple way to measure stroke efficiency: two swimmers can have the same speed, but the one with fewer strokes per length (a lower SWOLF) is moving more efficiently through the water.

Why does pool length affect anything besides the split table?

It doesn't change your overall pace or time, but it does change the length count and per-length split — a 1000m swim is 20 lengths in a 50m pool but 40 lengths in a 25m pool, and each individual length obviously takes half as long in the shorter pool.

How accurate are the predicted race times for longer distances?

They're a straightforward linear projection from your current pace, which works reasonably well for estimating training paces but doesn't fully account for how endurance, pacing strategy, and fatigue change over much longer distances — treat the longer predictions as a ballpark, not a guarantee.

Can I enter time as just minutes and seconds instead of hours too?

Yes — the time fields accept either mm:ss or hh:mm:ss format and figure out which one you meant automatically, so "20:00" and "00:20:00" are both read the same way.

Does this work for open water swimming too?

Pace, time, and distance calculations work the same regardless of where you swim. The per-length split table specifically assumes a pool, though, since open water doesn't have discrete lengths to split into — for open water, focus on the pace and predicted-time figures instead.