How these heart-rate zones are built
Most “zone” charts start from an estimated maximum heart rate and then take percentages of that number. A very common classroom formula is Fox: HRmax = 220 − age. A large analysis by Tanaka, Monahan, and Seals (2001) found that 208 − 0.7 × age fit observed maxima better across a wide adult age range. This page defaults to Tanaka because it is less harsh on older adults than 220 − age, but neither formula is a measurement of your maximum. If you have a supervised test or a carefully observed race-finish heart rate you trust, enter that instead.
Percent-of-max zones here use 50–60%, 60–70%, 70–80%, 80–90%, and 90–100% of that maximum. Those cut-points are a common five-zone grid, not a universal standard. Coaches, watches, and papers disagree on the edges, especially for “Zone 2.” Treat the ranges as a starting map, not as a lab lactate threshold.
The optional Karvonen method uses heart-rate reserve: HR = HRrest + % × (HRmax − HRrest). Two people with the same age and the same max can have different Zone 2 ranges if their resting rates differ. A lower resting heart rate widens the reserve and usually lifts the beats-per-minute targets. Resting rate should be a true rest value. Do not use a post-coffee or post-walk reading and then treat Karvonen as more “scientific” than it is.
Heart-rate training is useful because it responds to heat, illness, poor sleep, and hills in a way that pace often does not. It is also messy: chest straps usually beat optical wrist sensors for intervals; caffeine and some medications change heart rate; and wrist readings lag at the start of a hard effort. If a number on this page disagrees with a watch, check which max formula and which zone method the watch uses before assuming one of them is broken.
This is not medical advice. Do not use a calculated zone to push through chest pain, unusual shortness of breath, dizziness, or a training plan you have been told to avoid. If you also want an aerobic-capacity estimate, try the VO2 max calculator. For a running workout, the pace calculator sits well next to these zones.
Frequently asked questions
Why is Tanaka the default instead of 220 − age?
Tanaka, Monahan, and Seals (2001) reported that 208 − 0.7 × age described measured maxima better than 220 − age in their data. 220 − age is still everywhere, including some gym posters, so it remains an option. A measured max, when you have a trustworthy one, beats both estimates.
What is “Zone 2” on this page?
Zone 2 is 60–70% of max HR (or 60–70% of reserve if you chose Karvonen). Other systems put Zone 2 at a different percentage or at a ventilatory or lactate threshold. If your coach or watch uses another definition, use that definition for training and treat this page as a transparent percentage chart.
Do I need a resting heart rate?
Only for the Karvonen option. Percent-of-max zones ignore resting rate. If you switch to Karvonen without a careful rest reading, the ranges will look precise and still be off.
Can I use this for cycling or rowing?
The max-HR formulas and percentage math do not care which sport you are in. The effort that actually produces a true max, and the heart rate you see at a given pace, can differ by sport. Use sport-specific feel and, when it matters, a sport-specific test.
Is a high or low max HR a health problem?
This page cannot answer that. People vary, and some medicines lower heart rate on purpose. Talk with a clinician about symptoms or about a number that worries you. Do not change medication or ignore symptoms because of a calculator.