Swim Calculator
Calculate your swimming pace, finish time, and training paces for pool and open water distances including triathlon swims.
How do you calculate swim pace per 100m for a triathlon?
Swim pace per 100m = total swim time in seconds ÷ (distance in metres ÷ 100). A 30-minute 1500m Olympic swim = 1,800s ÷ 15 = 2:00/100m. Add 5–10 sec/100m for open-water vs pool pace (sighting + wetsuit) and another 5 sec for mass-start drafting chaos. Use this calculator to set predicted splits for sprint, Olympic, 70.3 and Ironman swim legs.
- Sprint (750m): predicted time = pace/100m × 7.5
- Olympic (1,500m): pace × 15
- 70.3 (1,900m): pace × 19
- Ironman (3,800m): pace × 38
Predicted swim times by pace per 100m
Pre-computed finish times for common triathlon swim distances at four pace tiers. Use these to set a realistic target before the race and cross-check your calculator results.
| Pace per 100m | Sprint 750m | Olympic 1.5km | 70.3 1.9km | Ironman 3.8km |
|---|---|---|---|---|
| 1:30 | 11:15 | 22:30 | 28:30 | 57:00 |
| 1:45 | 13:08 | 26:15 | 33:15 | 1:06:30 |
| 2:00 | 15:00 | 30:00 | 38:00 | 1:16:00 |
| 2:15 | 16:53 | 33:45 | 42:45 | 1:25:30 |
| 2:30 | 18:45 | 37:30 | 47:30 | 1:35:00 |
Times are pool-equivalent. Add 5-15 sec per 100m for open water. See adjustment guidance below.
Open water vs pool: adjusting your pace
Open water swims are typically 5 to 15 seconds per 100m slower than pool swims. The main factors are sighting (lifting your head to navigate adds 3 to 5 sec/100m), course current or chop, mass-start contact, and the absence of wall pushoffs. Wetsuits offset most of this gap.
Without a wetsuit
- Add 8 to 15 sec per 100m to your pool pace
- Sighting alone costs 3 to 5 sec per 100m
- Choppy water or current adds a further 5 to 10 sec
With a wetsuit
- Wetsuit buoyancy improves pool pace by 3 to 7%
- Net open-water adjustment: 0 to 5 sec per 100m slower
- Strong swimmers may match or beat their pool pace
Practical rule: if you swim 1:50 per 100m in the pool, budget for 1:55 to 2:00 in a calm open-water wetsuit swim, or 2:00 to 2:10 without a wetsuit or in choppy conditions. Use the pace table above with these adjustments to set a realistic race target.
Swimming Calculator
Choose your calculation method and get personalized pace recommendations
Format: MM:SS (e.g., 1:30 for 1 minute 30 seconds per 100 meters)
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