Free Tool

80/20 Polarized Training Zone Calculator

Calculate training zones for Matt Fitzgerald's 80/20 polarized training method. 80% easy, 20% hard.

About 80/20 Polarized Training

The 80/20 approach, popularized by Matt Fitzgerald, is based on research showing elite endurance athletes spend approximately 80% of training time at low intensity (below VT1) and 20% at high intensity (above VT2), while minimizing time in the 'gray zone' between.

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.