Swim Pace Calculator

How to use this tool

1. Choose what to solve for: Pace, Time, or Distance.
2. Enter the two known values.
3. Read the pace, time, distance, pace per 50, and speed. Pool courses also show wall-to-wall lengths and time per length; open water has no wall-length count.

Swimming pace basics

Swim pace is typically expressed as time per 100 meters or 100 yards. Pool distances: a standard lap pool is 25 meters (SCM - short course meters) or 25 yards (SCY); Olympic pools are 50 meters (LCM - long course meters).

Swim pace benchmarks

Pace zones for training

Structuring swim training around pace zones - estimated from your known race pace or critical swim speed - is more effective than always swimming at one effort level:

• Zone 1 (recovery): ~60–70% of max effort; easy aerobic; long slow distance sets.
• Zone 2 (aerobic base): ~70–80%; building aerobic capacity; most of your weekly volume.
• Zone 3 (tempo): ~80–85%; comfortably hard; lactate threshold sets.
• Zone 4 (threshold): ~85–90%; hard effort sustainable for 15–20 min; CSS (Critical Swim Speed) pace.
• Zone 5 (VO₂ max): ~95%+; sprint sets, 25–50m repetitions with full recovery.

SCM to LCM conversion

Swimmers are typically 1.5–2% slower in a 50-metre long-course pool (LCM) compared to a 25-metre short-course pool (SCM/SCY) at the same effort level. This is because short-course pools allow more turns per 100m, and the push-off from each wall provides a brief speed boost.

A rough conversion: add approximately 2–3 seconds per 100m to your SCM pace to estimate your LCM equivalent pace. Elite swimmers' times may differ more due to highly refined turn and underwater dolphin kick technique.

Triathlon swim pacing

Open-water triathlon swimming differs significantly from pool swimming:

• Sighting: lifting your head to spot buoys disrupts your stroke and adds approximately 5–10 seconds per 100m compared to your pool pace.
• Wetsuit: a triathlon wetsuit increases buoyancy and reduces drag, typically adding 5–8% speed in open water compared to a pool swim in a swimsuit.
• Mass start and drafting: swimming directly behind another swimmer reduces drag by 15–20%. Position yourself behind a slightly faster swimmer in the first few hundred metres.