Heart-rate zones

How the heart-rate zone calculator works

Zones are bands of effort defined as a share of your maximum heart rate. This tool gives you five of them, from very easy recovery to maximum effort, and shows the beats per minute for each.

Step 1: max heart rate. If you don't know yours, the tool estimates it from age with the Tanaka formula, 208 − 0.7 × age, which fits population data better than the older 220 − age rule. Both are averages: real maximums vary by 10 bpm or more between people of the same age. A recorded value from a hard all-out effort beats any formula.

Step 2: choose a method.

• % of max HR multiplies your max by each percentage.
• Heart-rate reserve (the Karvonen method) works from the gap between resting and max: target = resting + % × (max − resting). Because it uses your resting heart rate, it responds to your fitness and is often preferred by experienced runners.

What the zones are for

• Zone 1, 50–60%: recovery, warm-ups and cool-downs.
• Zone 2, 60–70%: easy aerobic running, where most of your mileage belongs.
• Zone 3, 70–80%: steady, comfortably hard running.
• Zone 4, 80–90%: threshold effort for tempo runs.
• Zone 5, 90–100%: short, very hard intervals.

Limits

• This is one common model. Watch brands and coaches draw zone boundaries a little differently, so your device may show slightly different numbers.
• Heart rate drifts upward in heat, with dehydration, poor sleep, caffeine, illness and stress, and it lags behind effort during short intervals. A chest strap is more accurate than a wrist sensor for intervals.
• Use the talk test as a cross-check: in Zone 2 you should be able to speak in full sentences.
• If you have a heart condition or take medication that affects heart rate, such as beta blockers, ask your doctor before training by heart rate. This tool is not medical advice.

Looking for paces instead? Try the training pace chart.