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❤️ Heart Rate Zone Calculator

Find your 5 personalized training zones using the Karvonen method, which factors in your resting heart rate for a more accurate result than age alone.

ZoneIntensityBPM RangeFeel
Zone 150-60%0-0Very light, recovery
Zone 260-70%0-0Light, fat-burning, "easy pace"
Zone 370-80%0-0Moderate, aerobic base
Zone 480-90%0-0Hard, threshold
Zone 590-100%0-0Maximum effort

Estimated Max Heart Rate: 0 bpm

💡 How to Measure Resting Heart Rate: Check your pulse first thing in the morning, before getting out of bed, for the most accurate reading. A fitness tracker's overnight average works well too. Don't measure right after waking with an alarm — give yourself a minute to settle first.

Why We Use Karvonen Instead of a Simple Age Formula

The classic "220 minus your age" method only accounts for max heart rate, ignoring your resting heart rate entirely. Two people the same age can have very different cardiovascular fitness — a trained endurance athlete might have a resting heart rate of 45 bpm, while a sedentary person of the same age sits at 75 bpm. The Karvonen method factors in this difference through "heart rate reserve" (max HR minus resting HR), giving each person a more personalized zone range.

Why We Use the Tanaka Formula for Max Heart Rate

We estimate max heart rate using 208 − (0.7 × age) rather than the older "220 − age" formula. Research published after the original 220-age formula found Tanaka's version tracks more accurately across a wider age range, particularly for older adults, where 220-age tends to overestimate true max heart rate.

What Each Zone Is Actually For

Zone 2 gets the most attention in endurance training circles right now, and for good reason — training at this "easy" intensity for extended periods builds your aerobic base and fat-burning efficiency without the recovery cost of harder sessions. Zone 4-5 work builds speed and anaerobic capacity but needs far less weekly volume, since it's much more taxing to recover from. Most well-designed endurance programs spend 70-80% of total training time in Zones 1-2.

Frequently Asked Questions

How accurate is the Tanaka max heart rate formula?

It's a population-based estimate, so individual variation is normal — some people's true max heart rate sits 10-15 bpm above or below the formula's prediction. If you have a recent max heart rate from a supervised stress test or a maximal effort event, use that instead of the formula estimate.

Why does my fitness watch show different zones than this calculator?

Different devices use different formulas (some use simple percentage of max HR without the Karvonen heart-rate-reserve adjustment, some let you manually enter a known max HR). Differences of a few bpm between methods are normal — pick one method and stay consistent with it.

Should I train in Zone 5 often?

No. Zone 5 is maximum effort, sustainable for only short bursts, and very taxing to recover from. Most training plans use it sparingly — short intervals once or twice a week at most, not as a regular training zone.