How the zones are calculated
We estimate your maximum heart rate as 220 minus your age. The Karvonen method then uses your heart-rate reserve (max minus resting heart rate): target = reserve × intensity + resting. This personalises the zones to your fitness better than a percentage of max alone.
How to use it
Enter your age and resting heart rate (best measured first thing in the morning). Your five zones appear in beats per minute: warm-up, fat burn, cardio, anaerobic and maximum. Train in the zone that matches your goal.
Frequently asked questions
- Why use resting heart rate?
- The Karvonen method factors in your resting heart rate, so the zones reflect your individual fitness, not just your age.
- Which zone burns the most fat?
- The fat-burn zone uses a higher share of fat, but higher zones burn more total calories. Mix zones for best results.
- How do I find my resting heart rate?
- Measure your pulse for a full minute right after waking, before getting up, for a few days and average it.
- Is 220 − age accurate?
- It is a useful estimate but can be off by 10–12 bpm for some people. A lab test or chest-strap data is more precise.