Can I use yards instead of meters?

Yes. The calculator supports both meters and yards, and always returns pace for both 100m and 100yd so you can compare workouts.

What if I only know laps and pool length?

Switch to laps mode and enter lap count plus pool length. The calculator converts that into total distance automatically.

How is SWOLF estimated?

SWOLF is estimated from your pace, distance, stroke type, and pool length assumptions. It is a planning estimate, not a replacement for watch-based stroke counts.

What does the effort zone mean?

Effort zone classifies pace intensity from Recovery to Sprint using your pace per 100m. It helps you align sets with easy, tempo, threshold, or sprint work.

Is this tool free and private to use?

Yes. AI Fit Hub tools are free, no-signup browser tools. Inputs stay in your browser unless you choose to share a URL.

Do these tools replace medical guidance?

No. These outputs are general fitness estimates — not medical advice.

Methodology: Swim Pace Calculator

Scope

Calculates swim pace, total time, or distance for any two of the three, with SWOLF and effort context.

Formula

pace_per_100 = total_time / distance * 100. SWOLF = stroke_count + seconds per length.

Coefficients

Parameter	Value	Note
Pool length options	`25 m, 50 m, 25 yd`

Data sources

World Aquatics (formerly FINA) — Facilities Rules: pool dimensions and timing standards. — Federation specification for 25 m, 50 m, and short-course pool lengths and competition timing.
USA Swimming — Rules and Regulations: course-length and timing standards. — U.S. governing body for swimming course measurement and meet-time standards.

Assumptions

Pool length is accurate; open-water GPS adds substantial noise.

Approximation range

Arithmetic is exact; SWOLF trends reflect stroke efficiency over sessions.

Limitations

Pace does not capture stroke type, open-water conditions, or currents.

Reproducibility

1000 m in 18:00. Pace = 18*60/10 = 108 s/100 m = 1:48/100 m.

Change log

2026-04-24: methodology page first published.

Running Pace Calculator — Calculate pace per km and mile and project race finish times from one run.
VO2 Max Estimator — Estimate aerobic capacity with the Cooper 12-minute run or Rockport 1-mile walk field tests.
Walking Calorie Calculator — Estimate calories burned from walking using speed, duration, body weight, and incline.
Calories Burned Calculator — Estimate exercise calorie burn from body weight, duration, MET intensity, and incline.

Worked example

Computed by the same engine bundle served at /engines/swim-pace-calculator.js. Re-runnable: the values below are the literal output of compute(engineInput).

Input

tool: swim_pace_calculator
mode: pace
stroke_type: freestyle
distance_value: 1500
distance_unit: m
laps: 0
pool_length: 25
pool_length_unit: m
time_seconds: 1800
target_pace_seconds: 120
target_pace_unit: 100m

Output

distanceMeters: 1500
distanceYards: 1640.42
totalTimeSeconds: 1800
pacePer100mSeconds: 120
pacePer100ydSeconds: 109.73
swolfEstimate: 50
effortZone: Tempo
strokeType: freestyle

FAQ

Can I use yards instead of meters?: Yes. The calculator supports both meters and yards, and always returns pace for both 100m and 100yd so you can compare workouts.
What if I only know laps and pool length?: Switch to laps mode and enter lap count plus pool length. The calculator converts that into total distance automatically.
How is SWOLF estimated?: SWOLF is estimated from your pace, distance, stroke type, and pool length assumptions. It is a planning estimate, not a replacement for watch-based stroke counts.
What does the effort zone mean?: Effort zone classifies pace intensity from Recovery to Sprint using your pace per 100m. It helps you align sets with easy, tempo, threshold, or sprint work.
Is this tool free and private to use?: Yes. AI Fit Hub tools are free, no-signup browser tools. Inputs stay in your browser unless you choose to share a URL.
Do these tools replace medical guidance?: No. These outputs are general fitness estimates — not medical advice.