How to Use the Swim Pace Calculator
- Pick what to calculate: pace, finish time, distance, or a CSS test from a 400 and a 200.
- Enter the distance and its unit, or tap a pool or triathlon distance button.
- Enter your swim time in hours, minutes and seconds.
- Read your pace per 100, then check speed, pool lengths, splits and triathlon times.
Choose what you want to work out. Pace needs a distance and a time, Finish time needs a distance and a pace, and Distance needs a time and a pace. The field you are solving for is hidden. Distances can be in meters, yards, kilometers or miles, and pace can be per 100 m or per 100 yd. The race buttons fill in common pool and triathlon distances.
Every result shows pace in both units, your speed, the number of lengths in the pool you pick, even split times and how long the same pace would take over common triathlon swims. The CSS test tab turns a 400 and a 200 time trial into your critical swim speed, a popular training pace.
Swim Pace Formula
pace per 100 yd = pace per 100 m × 0.9144
pool lengths = distance ÷ pool length
CSS pace per 100 = (T400 − T200) ÷ 2
One yard is exactly 0.9144 m, so 100 yd is 91.44 m. Pace per 100 yd is therefore about 8.6% faster on the clock than pace per 100 m for the same speed.
Worked Example
Swimming 1500 m in 30:00 is 1,800 seconds ÷ 1,500 m = 1.2 seconds per meter, so the pace is 2:00 per 100 m. Per 100 yd that is 120 × 0.9144 = 109.7 seconds, or 1:50. The speed is 3.00 km/h (0.83 m/s), and the swim is 60 lengths of a 25 m pool. At the same pace a full Ironman swim of 3.8 km takes 1:16:00.
Critical Swim Speed (CSS) Test
Critical swim speed estimates the fastest pace you can sustain without tiring quickly, close to your threshold. After a good warm-up, swim 400 as hard as you can pace it evenly, rest fully, then swim 200 all out. The difference between the two times covers 200 units of distance, so dividing it by 2 gives seconds per 100.
Example: a 400 m in 6:40 (400 s) and a 200 m in 3:10 (190 s) give (400 − 190) ÷ 2 = 105 seconds, a CSS of 1:45 per 100 m. Repeat the test every 6 to 8 weeks to track progress.
Swim Pace Chart for Triathlon Distances
| Pace /100 m | 750 m | 1500 m | 1.9 km | 3.8 km |
|---|---|---|---|---|
| 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 |
Meters or Yards: Which Pace to Use
Use the unit of the pool you train in. Most pools in Canada and Europe are 25 m or 50 m, while many US school and college pools are 25 yd. A pace per 100 yd always looks faster on the clock than the same speed per 100 m, so compare like with like. Triathlon and open water distances are set in meters, so convert a yard pace before you plan a race. A 50 m pool also has half as many walls to push off as a 25 m pool, which is why most swimmers are a little slower per 100 in long course.
Tips and Limits
- Pool pace includes push-offs from the wall, which add free speed. Expect open water to be slower unless you wear a wetsuit.
- Pace math assumes an even effort. Most swimmers slow down over long distances, so add a margin for races longer than your usual training sets.
- Count lengths, not laps, when you compare with this tool. Some swimmers call one length a lap and others call a there-and-back a lap.
Results are estimates for general information, not medical advice. Talk with a doctor or registered dietitian before big changes to diet, exercise or sleep, especially if you are pregnant, under 18 or managing a health condition.
Frequently asked questions
How do I calculate my swim pace per 100 m?
Divide your time in seconds by the distance in meters and multiply by 100. For example, 1500 m in 30 minutes is 1,800 ÷ 1,500 × 100 = 120 seconds, a pace of 2:00 per 100 m.
How do I convert swim pace from meters to yards?
Multiply pace per 100 m by 0.9144, because 100 yards is 91.44 meters. A pace of 2:00 per 100 m equals about 1:50 per 100 yd. The calculator shows both every time.
What is a good swim pace for a beginner?
Many adult beginners swim 100 m in about 2:30 to 3:00 with steady freestyle. Regular swimmers often reach 1:45 to 2:15, and fast age group triathletes swim under 1:30.
How long does a 1.9 km triathlon swim take?
At 2:00 per 100 m it takes 38 minutes. At 1:45 per 100 m it takes 33:15. Enter your own pace in Finish time mode to plan your race.
What is CSS in swimming?
Critical swim speed is a threshold pace calculated from a 400 and a 200 time trial. Pace per 100 equals the 400 time minus the 200 time, divided by two.
How many lengths is 1500 m in a 25 m pool?
It is 60 lengths of a 25 m pool or 30 lengths of a 50 m pool. In a 25 yard pool, 1500 m is about 65.6 lengths.