Swim Training Pace Calculator
Calculate your target swim pace per 100m or 100 yards for different training zones.
Based on your CSS (Critical Swim Speed) or a recent race time.
Swim Training Zones Explained
Effective swim training uses different intensity zones. Training at the right intensity improves speed, endurance, and efficiency.
What Is CSS (Critical Swim Speed)?
Critical Swim Speed is the theoretical maximum pace you can sustain for a long distance without accumulating excessive lactic acid — roughly your threshold pace. It is estimated from two time trials: a 400m (or 400 yard) and a 200m (or 200 yard) effort.
CSS (seconds per 100m) = (400m time − 200m time) in seconds
For example:
- 400m in 6:00 (360 seconds), 200m in 2:45 (165 seconds)
- CSS = 360 − 165 = 195 seconds per 100m = 3:15/100m
Training Zones Based on CSS
| Zone | Name | % of CSS | Purpose |
|---|---|---|---|
| Zone 1 | Recovery | CSS + 20–30 sec | Active recovery, technique work |
| Zone 2 | Aerobic | CSS + 10–20 sec | Base endurance building |
| Zone 3 | Threshold | CSS ± 5 sec | Race-pace stamina |
| Zone 4 | VO2 Max | CSS − 5–10 sec | Speed and power |
| Zone 5 | Anaerobic | CSS − 10–20 sec | Sprint sets, short efforts |
Standard Pool Distances
| Pool Type | Length |
|---|---|
| Short course metric | 25 meters |
| Short course yards | 25 yards |
| Long course (Olympic) | 50 meters |
Training paces are typically expressed per 100m or per 100 yards. For 25m pools, divide by 4 to get your target time per length.
Converting Between Yards and Meters
1 yard = 0.9144 meters. To convert a pace per 100 yards to per 100 meters: multiply by 0.9144.