Heart Rate Zone Calculator
Enter your age to see your five heart-rate training zones in beats per minute.
How to use
- Enter your age.
- Optionally add your resting heart rate for more accurate zones (Karvonen method).
- Click Calculate to see all five zones.
For information only — not medical advice. Consult a healthcare professional for personal guidance.
What Is a Heart Rate Zone Calculator?
Heart rate zones divide your effort into bands, each of which trains your body differently. Easy zones build endurance and burn a high proportion of fat; hard zones build speed and maximum oxygen capacity but cannot be sustained for long. This calculator works out your personal zones from your age — and, if you know it, your resting heart rate — using the Karvonen method, so a "Zone 2 run" means the same relative effort for you as for anyone else, whatever your fitness level.
Training by heart rate solves the biggest problem with training by feel or by pace: both drift. Heat, hills, fatigue, poor sleep, and caffeine all change what a given pace demands from your heart. The heart rate itself is the demand, measured directly, which is why coaches across endurance sports prescribe intensity in zones rather than speeds.
How to Use the Heart Rate Zone Calculator
- Enter your age in years — this estimates your maximum heart rate.
- Optionally enter your resting heart rate in BPM, measured first thing in the morning before getting up. This enables the more personal Karvonen calculation.
- Click Calculate to see your five training zones with their BPM ranges.
- Use the ranges during workouts: most endurance training belongs in Zones 1–2, with small, deliberate doses of Zones 4–5.
The Karvonen Method and the Five Zones
Karvonen's insight was that effort should be scaled between your resting and maximum heart rates, not from zero. Target HR = resting HR + intensity × (max HR − resting HR). The difference (max − rest) is your heart rate reserve. The classic five zones are: Zone 1, 50–60% (warm-up, recovery), Zone 2, 60–70% (base endurance, conversational pace), Zone 3, 70–80% (aerobic endurance), Zone 4, 80–90% (lactate threshold), and Zone 5, 90–100% (maximum effort, sustainable only in short bursts).
Tips for Zone Training
- Measure resting heart rate over several mornings and use the average — one night's poor sleep can skew a single reading.
- Wrist-based heart rate monitors lag and can lock onto your cadence during running; a chest strap is the accuracy benchmark for hard intervals.
- Expect drift: on long efforts your heart rate climbs at a constant pace as you fatigue and heat up (cardiac drift) — slowing slightly to hold the zone is correct, not weakness.
How do I find my resting heart rate?
Measure it in bed, immediately after waking naturally, before coffee or activity: count your pulse for a full minute, or read it from a wearable's overnight data. Repeat over three to five mornings and average the results. Typical adult resting rates fall between 60 and 100 BPM, with trained endurance athletes often in the 40s and 50s.
Why does adding resting heart rate change my zones?
Because two people with the same maximum can have very different reserves. If your max is 180 and your resting rate is 50, your reserve is 130 beats; someone resting at 75 has a reserve of only 105. Karvonen zones account for that difference, so the same percentage represents a genuinely similar relative effort for both of you.
Which zone burns the most fat?
Zone 2 burns the highest proportion of fat during the workout, which earned it the "fat-burning zone" label — but higher zones burn more total calories and more total fat per minute. For weight loss, total energy balance over weeks matters far more than the fuel mix of any single session. Zone 2's real value is that you can accumulate lots of it without exhaustion.
Are these zones accurate for me?
They are estimates built on an age-predicted maximum, and true maximum heart rate varies between individuals by roughly ±10 BPM or more. If a zone feels clearly wrong — Zone 2 impossible to sustain, or Zone 5 comfortable — your true max probably differs from the formula. A supervised field test or lab test gives personal numbers; medications such as beta blockers also lower heart rate and require medical guidance.