Heart Rate Zones Calculator

What Your Result Means

For educational purposes only — not medical advice.

The results above show your personalised heart rate zones. Use these ranges to guide your training intensity each session.

Zone 2 should form the bulk (70-80%) of your training volume (Seiler & Tonnessen, 2009). This develops your aerobic base, improves mitochondrial density, and trains your body to burn fat efficiently. Zone 4-5 work should make up the remaining 20%. This "polarised" distribution — where you go easy on easy days and hard on hard days — was found to be superior to threshold-focused training across all six performance outcomes measured in trained athletes (Stoggl & Sperlich, 2014; DOI: 10.3389/fphys.2014.00033).

The most common mistake: Recreational athletes tend to train too hard on easy days and too easy on hard days, spending most of their time in Zone 3 — the "grey zone." This intensity is too low to stimulate VO₂max adaptation and too high to allow full recovery, leading to chronic fatigue and stalled progress. If you can't hold a conversation, you're above Zone 2.

HRmax accuracy: The "220 - age" formula has a standard deviation of ±10-12 bpm, meaning your actual max heart rate could be 20+ bpm different from the estimate. The Tanaka formula (208 - 0.7 × age) is more accurate (Tanaka et al. 2001; DOI: 10.1016/S0735-1097(00)01054-8), but a field max-effort test remains the best approach. If your zones feel wrong — easy runs feel too hard, or hard intervals feel too easy — your HRmax estimate is likely off.

Want to learn more? Read our in-depth article: Zone 2 Training: Why Slowing Down Makes You Faster →