Heart Rate Zone Calculator
Your 5 training heart-rate zones by age
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Heart-rate zones split training intensity into five bands of your maximum heart rate (220 minus age). Zone 2 is best for fat burning and endurance; zones 4–5 build speed. Adding resting heart rate uses the more personalised Karvonen (heart-rate reserve) method.
How to use this heart rate zone calculator
Enter your age and your five training zones are calculated instantly — no sign-up needed. Adding your resting heart rate (bpm) is optional but recommended: with it, the calculator switches from simple %HRmax zones to the more personalized Karvonen method. For the most accurate input, measure your resting heart rate in the morning before getting out of bed.
How to read your result
Zone 1 (50–60%) is very light effort for warm-ups and recovery, Zone 2 (60–70%) is the classic 'fat-burn' base-building zone where you can still hold a conversation, and Zone 3 (70–80%) builds aerobic fitness. Zone 4 (80–90%) trains your lactate threshold, while Zone 5 (90–100%) is short, maximal effort. Most endurance athletes benefit from spending roughly 80% of training time in Zones 1–2.
The formula and the science behind it
Maximum heart rate is estimated as 220 − age, the formula popularized by Fox and colleagues in 1971. If you enter a resting heart rate, zones are computed with the Karvonen method (1957): target = resting HR + (max HR − resting HR) × intensity. Because it works with your heart rate reserve, Karvonen reflects individual fitness better than plain %HRmax.
Limits and practical tips
220 − age is a population average — real maximums vary by ±10 bpm or more, and medications such as beta-blockers, plus caffeine, heat and stress, all shift heart rate. If you know your true maximum from a test or race, trust it over the formula. Pair this tool with our max heart rate, target heart rate and VO2 max calculators — and log your workouts and meals in the CaloNote app.
Frequently Asked Questions
- What is a heart rate zone calculator?
- A heart rate zone calculator estimates your five training zones in beats per minute based on your maximum heart rate. The zones range from light recovery to peak effort, helping you train at the right intensity for endurance, fat burning, or performance goals.
- What is the Karvonen method and why enter resting heart rate?
- The Karvonen method calculates zones from your heart rate reserve (max heart rate minus resting heart rate), which personalizes the result to your fitness level. Entering your resting heart rate makes the zones more accurate than using max heart rate alone.
- Which heart rate zone burns the most fat?
- Zone 2, roughly 60 to 70 percent of your max heart rate, uses the highest proportion of fat for fuel and is ideal for building aerobic base. Higher zones burn more total calories but rely more on carbohydrates.