How max heart rate is calculated
There's no way to know your exact max heart rate without a maximal exercise test, but age-based formulas give a reliable estimate for everyday training. This calculator shows three of the most widely used equations so you can compare them side by side.
- Fox: 220 − age (the classic, simplest estimate)
- Tanaka: 208 − 0.7 × age (more accurate across the adult age range)
- Gulati: 206 − 0.88 × age (validated specifically for women)
Which formula should you use?
The familiar 220 − age (Fox) formula is easy to remember but has a wide margin of error - it tends to overestimate max heart rate in younger people and underestimate it in older adults. The Tanaka formula, published in the Journal of the American College of Cardiology in 2001, is more accurate for the general adult population and is the modern default.
The Gulati formula was developed and validated specifically for women using data from thousands of female participants, and gives a lower, more realistic estimate for women than the older equations. That's why this calculator recommends Tanaka for men and Gulati for women.
Maximum heart rate by age
This table shows estimated maximum heart rate (in beats per minute) at different ages for each formula. Notice how the gap between the formulas grows at the younger and older ends of the range.
| Age | Fox (220 − age) | Tanaka | Gulati |
|---|---|---|---|
| 20 | 200 | 194 | 188 |
| 25 | 195 | 191 | 184 |
| 30 | 190 | 187 | 180 |
| 35 | 185 | 184 | 175 |
| 40 | 180 | 180 | 171 |
| 45 | 175 | 177 | 166 |
| 50 | 170 | 173 | 162 |
| 60 | 160 | 166 | 153 |
| 70 | 150 | 159 | 144 |
Your five heart-rate training zones
Once you know your max heart rate, training zones are simply percentages of it. Each zone develops a different aspect of fitness, from easy recovery work to maximal effort. The table below explains how each zone feels and what it does for you.
| Zone | % of max HR | How it feels | Main benefit |
|---|---|---|---|
| Zone 1 - Very light | 50–60% | Very easy, can chat freely | Warm-up and recovery |
| Zone 2 - Light | 60–70% | Comfortable, conversational | Endurance and fat burning |
| Zone 3 - Moderate | 70–80% | Breathing harder, short sentences | Aerobic fitness |
| Zone 4 - Hard | 80–90% | Uncomfortable, few words | Lactate threshold and speed |
| Zone 5 - Maximum | 90–100% | All-out, can't talk | Peak power and sprint capacity |
How to train with heart-rate zones
Most endurance and general-fitness plans follow an 80/20 split: roughly 80% of your training time in the easy Zones 1–2 and 20% in the hard Zones 4–5. This builds a large aerobic base while keeping fatigue manageable.
Zone 2 work improves your body's ability to burn fat and use oxygen efficiently, which is why it forms the bulk of most plans. Zone 4–5 intervals raise your lactate threshold and top-end speed. Spending too much time in the 'grey' Zone 3 - too hard to recover from, too easy to drive big adaptations - is a common mistake.
How to measure your true maximum heart rate
If you want a number more accurate than any formula, a supervised maximal field test will get you there. After a thorough warm-up, perform several minutes of progressively harder effort - for example repeated hard hill climbs or intervals - finishing with an all-out sprint, and record the highest reading on a chest-strap heart-rate monitor.
Because this is a maximal effort, it should only be attempted if you're healthy, used to intense exercise and ideally cleared by a doctor. Anyone with a heart condition, who is older or new to exercise should rely on the age-based estimate instead.
Factors that affect your max heart rate
Maximum heart rate is largely determined by age and genetics - not by fitness level. A fitter person doesn't have a higher max heart rate; instead they have a lower resting heart rate, recover faster, and can sustain a higher percentage of their max for longer. Heat, altitude, hydration, caffeine, medications (especially beta-blockers) and the type of exercise can all shift your readings on a given day, so treat any single number as an estimate rather than an exact limit.