What is a good CSS swim pace?
CSS is your threshold pace per 100 m, worked out from a 400 m and a 200 m time trial. What counts as good depends on your swimming background, age and pool. The tables below are references, not targets. Your own trend over several months says more than any table.
Open the Critical Swim Speed CalculatorCSS by level
This is a commonly used reference from the Swimer app for 50 m or 25 m pool freestyle.
| Level | CSS per 100 m | Estimated 400 m |
|---|---|---|
| Beginner | 2:10–2:30 | Over 9:00 |
| Low intermediate | 1:50–2:10 | 7:30–9:00 |
| Intermediate | 1:35–1:50 | 6:30–7:30 |
| Advanced | 1:20–1:35 | 5:30–6:30 |
| Elite | Under 1:20 | Under 5:30 |
CSS by age in competition swimmers
Swimer also worked out CSS from official 200 m and 400 m freestyle bests of 6,050 swimmers in 50 m pools (snapshot August 2026). These are competition swimmers, so most triathletes will be slower.
| Age | Women | Men |
|---|---|---|
| 25–34 | 1:20.2 | 1:16.1 |
| 35–44 | 1:21.6 | 1:16.4 |
| 45–54 | 1:36.6 | 1:29.3 |
| 55+ | 1:45.8 | 1:37.5 |
Reading your result
- CSS pace per 100 m is (400 m time in seconds minus 200 m time in seconds) ÷ 2.
- Compare yourself with your own past tests first. A drop of a few seconds per 100 m is a real gain.
- Pool CSS does not directly predict race pace in open water. See the CSS test guide for the limits.
FAQ
What is a good CSS for a beginner triathlete?
The level table puts beginners at 2:10–2:30 per 100 m. Your own trend matters more than the starting number.
Is a 1:40 CSS good?
On the level table 1:40 is intermediate. It is a solid pace for age-group triathlon.
Does pool length change CSS?
Yes. Push-offs help in short pools, so test in the pool where you train and keep using the same one.