Pace per 100m is to swimming what pace per mile is to running. It’s your single most useful training metric. Once you understand it, every workout becomes more purposeful.
What Is Pace Per 100m?
It’s the time it takes you to swim 100 meters at a given effort level. Expressed as minutes:seconds — so 1:45/100m means one minute 45 seconds per 100 meters.
If you swim 400m in 7 minutes flat, your pace is 1:45/100m. Simple.
How to Calculate It
Formula: Pace = Total time ÷ (Total distance ÷ 100)
Examples:
- 200m in 3:20 → 3:20 ÷ 2 = 1:40/100m
- 1000m in 18:00 → 18:00 ÷ 10 = 1:48/100m
- 400m in 6:40 → 6:40 ÷ 4 = 1:40/100m
Your smartwatch calculates this automatically. SwimBeat and other apps display it per session.
Finding Your Training Paces
The most useful thing you can do is establish a baseline — your current comfortable pace for a moderate 400–600m effort. Here’s how:
- Warm up for 400m easy
- Swim 400m at a pace that’s challenging but sustainable (not all-out)
- Note your time
- Calculate your pace per 100m
That number is your threshold pace. Use it as the anchor for your training zones:
| Zone | Pace relative to threshold |
|---|---|
| Easy/recovery | +15–20 sec/100m |
| Aerobic base | +5–10 sec/100m |
| Threshold | ±2–3 sec/100m |
| Speed work | -5 to -10 sec/100m |
Using Pace in Interval Sets
Once you have your training paces, interval sets become much more structured.
Instead of “swim 8×100m on 1:50,” you swim “8×100m targeting 1:40 threshold pace, with :10 rest.”
The interval (1:50) gives you the schedule. The target pace (1:40) gives you the intention. Both matter.
If you’re consistently hitting 1:38–1:42, you’re executing the set correctly. If you’re going 1:32 on rep 1 and 1:52 by rep 8, your pacing or fitness needs work.
Tracking Pace Improvement
The simplest way to track fitness progress is to swim the same time trial every 4–6 weeks and compare your pace. A 400m time trial at consistent effort is easy to repeat and directly comparable.
Apps like SwimBeat make this easy by storing your session history — you can pull up every 400m time trial you’ve done and see the trend over time.
One Important Note on Pool Length
Pace per 100m is specific to pool length. Your time in a 25m pool isn’t directly comparable to a 50m pool, because wall pushes add time in a 25m pool.
Most apps and watches account for this automatically when you set your pool length correctly. Always verify this setting before recording a session.
A Simple Starting Workout
New to pace training? Try this:
- 400m warm-up easy
- 4×100m at threshold pace, 20 sec rest
- 200m easy
- 4×100m at threshold pace minus 5 seconds (slightly faster), 30 sec rest
- 200m cool-down
Note your actual splits for each 100m. Compare to your target. That’s pace training.