What maximum heart rate is
Your maximum heart rate (HRmax) is the highest number of beats per minute your heart reaches during all-out effort. It is mostly determined by age and genetics, not fitness, and it slowly declines as you get older. Training zones, including the popular zone 2, are usually set as percentages of it.
The only way to know your true max is to measure it during a hard, supervised exercise test. Most people instead estimate it from their age. This calculator shows several well-known formulas side by side, so you can see how much the estimates differ.
The formulas
- Fox (220 − age) is the classic, easy-to-remember rule. It was not derived from a rigorous study and tends to underestimate max heart rate in older adults.
- Tanaka (2001) came from a large analysis of many studies of healthy adults and is widely used as a better general-purpose estimate.
- Gellish (2007) came from repeated treadmill tests of adults over many years and gives results very close to Tanaka.
- Nes (2013) came from a large Norwegian population study, the HUNT study, and gives somewhat higher estimates.
- Gulati (2010) was developed from treadmill tests in thousands of women and gives lower values for women, especially at older ages.
Worked example
For a 45-year-old woman the formulas give: Fox 175, Tanaka 176.5, Gellish 175.5, Nes 182.2 and Gulati 166.4 bpm. The average is about 175 bpm.
Using Tanaka's 176.5 bpm, her zone 2 (60–70%) is roughly 106–124 bpm and zone 4 (80–90%) is about 141–159 bpm.
How accurate are these estimates?
Every formula describes an average. Individuals of the same age commonly differ from the prediction by 10 beats per minute or more in either direction. If your chest strap regularly shows heart rates above your "max" during hard efforts, your real max is probably higher than the formula suggests.
Ways to get a better number:
- A supervised lab or clinical exercise test, which is the most accurate and the safest.
- The highest reading you have seen with a chest strap during a hard race or interval session.
- Using heart rate reserve (the Karvonen method), which also accounts for your resting heart rate. Our zone 2 heart rate calculator supports it.
Safety first
You do not need to reach your maximum heart rate to train well; most training happens well below it. Do not attempt a maximal test on your own if you are new to exercise, have heart disease or risk factors, or take medication that affects heart rate. Talk to your doctor first.
Frequently asked questions
What is my max heart rate at 40?
About 180 bpm by both 220 − age and the Tanaka formula. Gellish gives 179 bpm and Nes about 185 bpm. Your true max could be 10 or more beats higher or lower.
Is 220 minus age accurate?
It is a rough rule of thumb. Research-based formulas such as Tanaka are generally considered more accurate, especially for adults over 40.
Does fitness change max heart rate?
Not much. Training mainly lowers your resting heart rate and lets you work harder at a given heart rate. Max heart rate is mostly set by age and genetics.
Why is there a separate formula for women?
The Gulati formula came from a large study of women and found that the standard formulas tend to overestimate max heart rate in women, particularly as they get older.
Is it dangerous to exceed my max heart rate?
If your heart rate goes above the formula value, it usually just means your true max is higher than estimated. However, chest pain, dizziness or unusual shortness of breath are reasons to stop and seek medical advice.
Last reviewed November 2026. Spotted an error? Tell us.