Heart Rate Zones Calculator — max HR and AHA training zones by age

How it works

Everything starts from your maximum heart rate — the fastest your heart can beat, which falls steadily with age. It's hard to measure directly, so it's estimated from age. The familiar formula, the one the American Heart Association publishes, is 220 minus your age. A more accurate research-based alternative from a 2001 meta-analysis is 208 − 0.7 × age; you can pick either here. The two agree around age 40 and diverge at the extremes — 220 − age runs a little high for young adults and low for older ones, which is what the Tanaka equation was designed to correct.

Zones are then simple percentages of that maximum. The AHA marks two: moderate intensity at 50–70% of maximum — the range for building general fitness where you can still talk — and vigorous at 70–85%, where you're working hard and breathing heavily. The reference ladder on this page turns any percentage into bpm, so you can find the number for any intensity, not just the two named bands.

Worked example

For a 30-year-old using 220 − age:

• Maximum heart rate: 220 − 30 = 190 bpm.
• Moderate zone (50–70%): 190 × 0.5 = 95 up to 190 × 0.7 = 133, so about 95–133 bpm.
• Vigorous zone (70–85%): 190 × 0.7 = 133 up to 190 × 0.85 = 162, so about 133–162 bpm.

The moderate ceiling and vigorous floor meet at 70% (133 bpm) — that's the line between "comfortably hard" and "genuinely hard". Switching to the Tanaka formula at, say, age 25 gives a maximum of 208 − 17.5 = 190.5 rather than 195, nudging every zone down a little.

Frequently asked questions

How accurate is an age-predicted maximum heart rate?

It's an estimate with real scatter — individual maximums vary by roughly ±10–12 beats per minute around the age prediction, so two 40-year-olds can differ by 20 bpm. The formula gives a sensible starting point, but the only accurate way to know your true maximum is a supervised maximal exercise test. Treat the zones as guides, and let perceived effort and how you feel refine them.

Should I use 220 − age or the Tanaka formula?

For most people the difference is small and either is fine. 220 − age is the familiar standard and what most charts and machines use; Tanaka's 208 − 0.7 × age is better validated across ages and tends to be more accurate for people well under or over 40. If you're young or older and want the closer estimate, use Tanaka.

What's the difference between the moderate and vigorous zones?

Intensity. Moderate (50–70% of maximum) is the "talk test" range — you can hold a conversation, and it's where general health and endurance are built. Vigorous (70–85%) is harder: breathing is heavy, talking is difficult, and it drives bigger gains in fitness in less time. Both are useful; a mix across the week suits most people.

Is there a "fat-burning zone"?

The idea that a specific low zone burns more fat is misleading. At lower intensities a larger *proportion* of energy comes from fat, but higher intensities burn more total calories and often more total fat per minute. For weight management, total energy burned matters more than the zone — see the calories-burned and calorie calculators.

Why does maximum heart rate fall with age?

It's a normal feature of the ageing heart — changes in the electrical pacemaker and the heart's responsiveness reduce the peak rate achievable, independent of fitness. Being fit lowers your *resting* heart rate and raises your capacity, but it doesn't meaningfully raise your maximum, which is why the formulas depend on age rather than fitness.

Should everyone train in these zones?

They're general guidance for healthy adults. If you have a heart condition, take medication that affects heart rate (beta-blockers lower both resting and maximum rate substantially), are pregnant, or are new to exercise, the age-predicted zones may not apply and you should get individualised advice. Stop and seek help for chest pain, dizziness or unusual breathlessness regardless of the numbers.

What does this exclude?

It doesn't measure your actual maximum, account for medication, altitude, heat, caffeine or stress (all of which shift heart rate), or use the heart-rate-reserve method that factors in your resting rate — for that, see the target heart rate calculator. It gives population-average zones from age alone.