How do I find my real maximum heart rate?

Formulas like 220 minus age are population averages with an error of plus or minus 10-15 bpm for individuals. The highest number you have ever seen on a chest strap at the end of a hard race or hill-sprint session is a better estimate. Field test (if healthy and warmed up): several hard uphill efforts to failure, and take the peak reading.

What is the Karvonen method?

Karvonen bases zones on your heart rate reserve - the span between resting and maximum heart rate - rather than max alone: target = resting + percentage x (max - resting). Because it accounts for your resting HR, it personalises zones better, especially for fitter athletes with low resting rates.

Which zone should most of my running be in?

For endurance sports, most successful training is polarised: roughly 80% of weekly time easy (zones 1-2) and 20% hard (zones 4-5), with zone 3 used sparingly. The commonest training error is drifting easy runs into zone 3 - too hard to recover from, too easy to improve from.

Heart rate zones calculator

Work out your five training zones from your max heart rate, or personalise them properly with the Karvonen method if you know your resting heart rate.

Max heart rate

Max HR (bpm)

Highest you've seen on a chest strap

Resting HR (bpm) - optional

Enables Karvonen zones - morning pulse before getting up

The five zones

Zone 1 - recovery. Genuinely easy. Warm-ups, cool-downs, the day after a race.
Zone 2 - endurance. Conversational. Where most of your weekly volume belongs - this is the engine-building zone.
Zone 3 - tempo. "Comfortably hard". Useful in doses; the classic trap is living here by accident.
Zone 4 - threshold. Around the effort you could race for an hour. Cruise intervals, tempo blocks.
Zone 5 - VO2max. 3-8 minute race effort and above. Short intervals, big recovery.

Max HR: formulas versus reality

This tool's age estimate uses Tanaka (208 − 0.7 × age), which beats the old 220 − age across most adults - but any formula carries ±10-15 bpm of individual error. If you own a chest strap, the highest reading from a hard race finish or hill-sprint session is a better max than any equation. Wrist optical sensors under-read at high intensity; trust straps for this.

Why resting HR makes zones better

Two runners with a max of 190 but resting rates of 40 and 70 are physiologically different people. The Karvonen method zones on your heart rate reserve (max − resting), so the fit runner's easy zone sits higher in raw bpm - which matches how it actually feels. If you gave a resting HR, the table above is Karvonen; if not, it's simple %max.

FAQs

My easy zone feels impossibly slow. Is it wrong?

Probably not, because that reaction is nearly universal. If you've trained by feel for years, true zone 2 feels pedestrian for the first month. Hold the discipline and the aerobic gains follow.

Should I use HR zones for intervals?

Use them carefully. Heart rate lags effort by a minute or more, so short reps finish before your HR catches up. Zones work best for steady running, so judge short intervals by pace or feel instead.

Do zones change as I get fitter?

Your resting HR drops and paces within zones get faster; max HR barely trains. Re-run the calculator when your resting HR shifts by more than a few bpm.