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Free tool

Heart rate
zone calculator

Enter your age (or your known max heart rate) and get your 5 training zones in beats per minute — the same five zones your Garmin uses. Train easy days easy and hard days hard, instead of grinding everything in the grey middle.

We estimate max HR as 220 − age.
From a lab test or hard race. Overrides the estimate.
Enables the Karvonen method.

How heart rate zones work

Your zones are percentages of your maximum heart rate. Most runners spend too much time in Zone 3 — too hard to recover from, too easy to build real speed. The fix is the classic 80/20 split: roughly 80% of your week easy (Zone 1–2) and 20% hard (Zone 4–5).

The Garmin connection: your watch already records which zone every minute of every run was in — but it won't tell you which zone today's run should be. That's the job Custom Gains does: it sets the target zone for each workout based on your goal and recovery, and sends it to your watch.

FAQ

How do I calculate my heart rate zones?

Estimate your max HR (220 − age is the common rule of thumb), then take percentages: Zone 1 is 50–60%, Zone 2 60–70%, Zone 3 70–80%, Zone 4 80–90%, Zone 5 90–100%. If you enter your resting HR above, we also show the Karvonen (heart-rate reserve) version, which is more personal.

Are these the same zones Garmin uses?

Yes — Garmin's default is this same 5-zone percentage-of-max model. If you've set a max or lactate-threshold HR on your watch, Garmin uses that instead of the age estimate.

What is Zone 2 training?

Easy aerobic effort (≈60–70% of max HR) where you can still talk. Most of your weekly volume should live here to build endurance without wrecking recovery.

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This calculator gives general training estimates, not medical advice. Check with a doctor before starting a new training program.