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Swim pace chart: what your 100 m pace means over any distance
One number — your pace per 100 m — tells you what you can swim over 400 m, over 1,500 m and over an Ironman swim, and how fast every set in your week should be.
written by jan hercog & rubsterbest · updated August 2026
How to read this chart
The first column is your threshold pace per 100 m — in practice, your Critical Swim Speed. The race columns apply a realistic drift: 400 m is swum slightly faster than threshold, 1,500 m slightly slower, and long open-water swims slower again, because sighting, wetsuit fatigue and lack of walls all cost time.
These are pool-honest estimates for a continuous front-crawl swim, not a promise. Use them to set targets.
| Threshold / 100 m | 400 m | 1,500 m | 1.9 km | 3.8 km |
|---|---|---|---|---|
| 1:10 | 4:32 | 17:51 | 23:03 | 47:26 |
| 1:15 | 4:51 | 19:08 | 24:42 | 50:50 |
| 1:20 | 5:10 | 20:24 | 26:21 | 54:13 |
| 1:25 | 5:30 | 21:41 | 28:00 | 57:36 |
| 1:30 | 5:49 | 22:57 | 29:38 | 1:00:59 |
| 1:35 | 6:09 | 24:14 | 31:17 | 1:04:23 |
| 1:40 | 6:28 | 25:30 | 32:56 | 1:07:46 |
| 1:45 | 6:47 | 26:47 | 34:35 | 1:11:09 |
| 1:50 | 7:07 | 28:03 | 36:14 | 1:14:33 |
| 1:55 | 7:26 | 29:20 | 37:52 | 1:17:56 |
| 2:00 | 7:46 | 30:36 | 39:31 | 1:21:19 |
| 2:10 | 8:24 | 33:09 | 42:49 | 1:28:06 |
| 2:20 | 9:03 | 35:42 | 46:06 | 1:34:52 |
| 2:30 | 9:42 | 38:15 | 49:24 | 1:41:39 |
Training paces for the same swimmer
Racing is one thing; training is where the pace chart earns its keep. Every zone is a share of threshold pace, so the same single number gives you the target time for a recovery 200, an aerobic 400 and a speed-endurance 50.
| Threshold / 100 m | Z2 easy | Z3 aerobic | Z4 threshold | Z5 VO2 |
|---|---|---|---|---|
| 1:15 | 1:26 | 1:21 | 1:16 | 1:13 |
| 1:25 | 1:38 | 1:32 | 1:26 | 1:22 |
| 1:35 | 1:49 | 1:43 | 1:36 | 1:32 |
| 1:45 | 2:01 | 1:53 | 1:46 | 1:42 |
| 1:55 | 2:12 | 2:04 | 1:56 | 1:52 |
| 2:10 | 2:30 | 2:20 | 2:11 | 2:06 |
Per 100 m, per 50 m, per length
In a 25 m pool your per-length split is a quarter of your 100 m pace: 1:40 per 100 m is 25 seconds per length. In a 50 m pool it is half. Counting a couple of lengths mid-set is the quickest way to know whether you are drifting, without staring at the clock on every wall.
What to do with your number
- Test it properly once — the 400/200 protocol takes 25 minutes.
- Save it to your account so every session prints your target time on each rep.
- Retest every six to eight weeks and watch the chart row move up.
If you would rather not do the arithmetic, the free CSS calculator does all of it — and The generator writes the target times straight into your session.