Free Tool

Swimming Training Zone Calculator

Calculate swimming training zones using Critical Swim Speed. Includes pace zones for pool and open water.

About Swimming Zones

Swimming training zones are primarily pace-based since heart rate response is different in water (lower max HR, delayed response). Critical Swim Speed provides the threshold anchor for all swimming training zones.

Auto-Calculate from Your Data

Upload Strava, Garmin, or Intervals.icu exports to estimate your zones

Strava vs Garmin vs TrainingPeaks: Zone Differences

Different platforms calculate training zones differently. Here's what each expects:

Strava
Zone System 5-zone (% Max HR)
Algorithm % Max HR
Customizable No

Uses simple % of max HR. Zones are fixed percentages. Cannot customize.

Garmin
Zone System 5-zone (customizable)
Algorithm % Max HR or % HRR
Customizable Yes

Supports both %Max HR and %HRR (Heart Rate Reserve). Fully customizable zones.

TrainingPeaks
Zone System 5 or 7 zone
Algorithm % LTHR (Joe Friel)
Customizable Yes

Uses LTHR-based zones. Supports pace, HR, and power. Highly customizable.

Polar
Zone System 5-zone
Algorithm % Max HR or % HRR
Customizable Yes

Uses either method. Includes sport profiles with different zone settings.