What heart rate zones are for
Heart rate zones divide exercise intensity into bands, each linked with a different training effect. Easy zones build endurance, support recovery and let you train for a long time. Hard zones improve speed and the ability to tolerate intense effort, but they cost far more fatigue and can only fill a small share of a sensible week. Knowing your zones turns a vague instruction like go easy or push hard into a number you can check on a watch or by feel.
Every zone system starts from your maximum heart rate, the highest rate your heart can reach in an all-out effort. Because a true maximum test is exhausting and unsuitable for many people, calculators estimate it. The classic estimate is 220 minus age; the Tanaka estimate, 208 minus 0.7 times age, was fitted to a large research dataset and is shown here as a comparison. Both are population averages: your true maximum can easily be 10 or more beats away from either figure. This page is for information only and is not medical advice, and it is not a substitute for a supervised exercise test.
The Karvonen method
The difference between maximum and resting heart rate is your heart rate reserve. Karvonen zones take a percentage of that reserve and add your resting rate back, which personalises the zones: a fitter person with a low resting rate gets different zones from someone of the same age with a higher resting rate. Enter a resting heart rate above zero to use Karvonen here; enter 0 and the page falls back to simple percentages of maximum heart rate.
The five zones
Zone 1, Recovery (50-60%): very easy movement, warm-ups and recovery days; you can speak in full sentences easily. Zone 2, Fat burn (60-70%): comfortable endurance pace, the base of most training; conversation is still possible. Zone 3, Aerobic (70-80%): a purposeful, moderately hard effort that builds stamina; speech becomes broken. Zone 4, Threshold (80-90%): hard and only sustainable for limited periods; it trains your body to work near its sustainable ceiling. Zone 5, Peak (90-100%): near-maximal efforts in short bursts, used sparingly by experienced exercisers.
Worked example
A 30-year-old has an estimated maximum of 220 − 30 = 190 bpm (Tanaka: 208 − 21 = 187). With a resting rate of 60 bpm, heart rate reserve is 130. Karvonen zones are: Zone 1, 60 + 50-60% of 130 = 125-138; Zone 2, 138-151; Zone 3, 151-164; Zone 4, 164-177; Zone 5, 177-190 bpm.
How to use this calculator
- Enter your age.
- Measure your resting heart rate on waking, before getting up, and enter it; enter 0 to ignore it.
- Read your estimated maximum heart rate and the Tanaka comparison.
- Find your five zones in the table and the bar chart.
- Use lower zones for most training and treat the highest zones with respect.
Limits of heart rate formulas
Age-based maximum formulas are convenient and imprecise. Genetics, fitness, heat, altitude, caffeine, fatigue, illness and several common medicines, especially beta blockers, all move heart rate responses. A chest strap measures more accurately than a wrist sensor during intervals and cold weather. Perceived effort and the talk test remain valuable checks: if Zone 2 feels like a struggle to breathe, the formula, not your body, is probably wrong.
Stop exercising and seek medical help promptly for chest pain, severe breathlessness, dizziness or palpitations. If you are new to exercise, returning after illness, pregnant, or managing a heart or other health condition, get personalised clearance and guidance from a qualified professional before training in high zones. This calculator supports general education only and is not medical advice.
Important note
For information only — not medical advice. This calculator uses standard published formulas to estimate values for general education and planning. It does not diagnose, treat, or replace the advice of a doctor or other qualified health professional. If you have a health concern, are pregnant, or are making decisions about treatment, medication, or a major diet or exercise change, please talk to a healthcare professional first.