The quickest way to estimate your max heart rate is to subtract your age from 220. A 40-year-old, for example, gets an estimated max of 180 beats per minute. This formula has been the standard for nearly four decades, but it’s far from perfect, and better options exist depending on your age, sex, and how precise you need the number to be.
The Standard Formula: 220 Minus Age
The Fox formula (220 minus your age) is what you’ll see on most gym posters, fitness trackers, and treadmill displays. It’s popular because it’s simple. But the standard deviation is about 11 beats per minute, meaning your true max heart rate could easily be 10 or more beats higher or lower than the formula predicts. For a 50-year-old, the estimate is 170, but the real number could fall anywhere from roughly 159 to 181.
That margin of error matters if you’re using max heart rate to set training zones. Being off by 10 beats shifts every zone you calculate from it, which can leave you training too easy or too hard.
A More Accurate Formula for Most People
A revised formula, developed by researcher Hirofumi Tanaka, adjusts for the fact that max heart rate doesn’t drop at a perfectly steady rate as you age. The calculation is:
208 minus (0.7 × your age)
For a 40-year-old, this gives 180, the same result as the old formula. But the two diverge at other ages. A 25-year-old gets 190.5 with Tanaka’s formula versus 195 with the standard one. A 60-year-old gets 166 versus 160. The Tanaka formula generally performs better across a wider range of ages and fitness levels, making it a stronger starting point if you want a quick estimate without a physical test.
Why Women Should Use a Different Number
The 220-minus-age formula was built from studies conducted almost entirely on men. Research led by cardiologist Martha Gulati found that women’s max heart rates decline with age at a different rate, and developed a sex-specific formula:
206 minus (0.88 × your age)
A 45-year-old woman, for instance, gets a predicted max of about 166 with this formula, compared to 175 from the standard one. That nine-beat gap has real consequences. Using the old formula, doctors were more likely to give women a worse prognosis than they actually had during cardiac stress tests, because many women couldn’t reach target heart rates that were set too high. The Gulati formula gives physicians and exercisers a more accurate baseline for assessing both fitness and heart health in women.
How to Measure It Directly
Formulas are estimates. If you want your actual number, you need to push your heart rate to its ceiling during a controlled effort. The Cardiac Exercise Research Group at the Norwegian University of Science and Technology recommends a protocol you can do on a track, bike, rower, or in a pool:
- Warm up thoroughly until you’re sweating.
- Do two four-minute intervals at an intensity where you’re too breathless to hold a conversation, with three minutes of easy movement between them.
- Start a third interval, but after two minutes, increase your effort and go as hard as you can until you physically can’t continue.
The highest number your heart rate monitor records during that final push is your max. Your heart reaches a plateau where it simply won’t beat any faster no matter how much harder you try. If you don’t have a monitor, press two fingers against the side of your neck immediately after finishing, count beats for 30 seconds, and double that number.
This kind of test is demanding. It requires a solid fitness base and the willingness to push to genuine exhaustion. If you have any cardiovascular risk factors, a supervised treadmill stress test with a clinician is the safer route and gives even more precise results.
Medications That Change the Math
Beta blockers, commonly prescribed for high blood pressure and certain heart conditions, block adrenaline receptors in the heart. Since adrenaline is what drives your heart rate up during intense effort, beta blockers lower your max heart rate by an unpredictable amount. No formula can account for this. You may never reach the target heart rate a formula gives you, no matter how hard you push.
If you take beta blockers, a supervised exercise stress test is the most reliable way to find your adjusted max. An alternative is to skip heart rate targets entirely and use a perceived exertion scale instead. The Borg scale, for example, has you rate how hard you feel you’re working. Most workouts should feel challenging but sustainable. A practical shortcut: if you can still talk in short sentences, you’re in a solid moderate-to-vigorous range.
Turning Max Heart Rate Into Training Zones
Once you have your max heart rate, you can set intensity targets for your workouts. The two most commonly referenced zones:
- Moderate intensity: 50% to 70% of your max. This covers brisk walking, easy jogging, and casual cycling. You can carry on a conversation.
- Vigorous intensity: 70% to 85% of your max. This is tempo running, faster cycling, or a hard group fitness class. Talking becomes difficult.
To calculate your zone, multiply your max heart rate by the percentages. If your max is 180, moderate intensity falls between 90 and 126 beats per minute, and vigorous intensity spans 126 to 153. Most general fitness guidelines recommend at least 150 minutes per week in the moderate zone or 75 minutes in the vigorous zone.
Keep in mind that these zones are only as accurate as the max heart rate you plug in. If you’re using the 220-minus-age estimate and it happens to be 11 beats off, your zone boundaries will be shifted too. That’s fine for general health purposes, but if you’re training for performance, a direct test or a more tailored formula gives you better numbers to work with.