To calculate your target heart rate, you first need your maximum heart rate, then multiply it by the intensity percentage that matches your fitness goal. The most common formula puts maximum heart rate at 220 minus your age, which means a 40-year-old has an estimated max of 180 beats per minute. Your target zone for moderate exercise falls between 50% and 70% of that number, and vigorous exercise sits between 70% and 85%.
That’s the quick version. But which formula you use, whether you factor in your resting heart rate, and how you measure your baseline all affect the accuracy of your number. Here’s how to do it properly.
Step 1: Measure Your Resting Heart Rate
Before running any formula, you need a reliable resting heart rate. This matters especially if you plan to use the more precise Karvonen method (covered below), but it’s also a useful baseline for tracking your fitness over time.
Place your index and middle finger on your wrist just below the thumb, or along either side of your neck, so you can feel your pulse. Count the beats for 30 seconds and double the number. Repeat a few times to make sure you’re getting a consistent reading. The best time to do this is first thing in the morning before you get out of bed. Don’t measure within one to two hours after exercise or a stressful event, and wait at least an hour after caffeine. Checking a few times per week at different times of day gives you the most reliable average.
A typical resting heart rate for adults falls between 60 and 100 beats per minute, though people who are physically active often land in the 50s or even 40s.
Step 2: Estimate Your Maximum Heart Rate
Your maximum heart rate is the fastest your heart can beat during all-out exertion. Since pushing yourself to that limit in a test isn’t practical (or safe) for most people, formulas give you a reasonable estimate.
The Standard Formula
The most widely used equation is simply 220 minus your age. A 30-year-old gets a max of 190; a 55-year-old gets 165. It’s simple and has been the default in gyms and doctor’s offices for decades. The catch is that research spanning more than two decades shows this formula carries an error of 7 to 11 beats per minute in either direction. For most people doing general fitness training, that’s close enough. But it systematically underestimates max heart rate in older adults, which can lead to exercise prescriptions that are too easy.
The Tanaka Formula (More Accurate for Older Adults)
A large-scale analysis published in the Journal of the American College of Cardiology produced a refined equation: 208 minus 0.7 times your age. For a 30-year-old, that gives 187. For a 60-year-old, it gives 166 compared to the standard formula’s 160. The difference grows with age, which is exactly the gap the standard formula misses. Cleveland Clinic references a nearly identical version: multiply your age by 0.7, then subtract from 207.
The Gulati Formula (For Women)
The standard 220-minus-age equation was built on studies of men. Research from a large cohort of women produced a sex-specific formula: 206 minus 88% of your age. For a 40-year-old woman, that’s 206 minus 35.2, giving a max of about 171. Women have different physiologic responses to exercise, and this formula reflects that difference in exercise capacity. If you’re a woman, this version will generally give you a more accurate starting point.
Step 3: Pick Your Intensity Zone
The American Heart Association defines two primary training bands based on percentage of maximum heart rate:
- Moderate intensity: 50% to 70% of your max
- Vigorous intensity: 70% to 85% of your max
So a 45-year-old using the standard formula (max of 175) would aim for 88 to 123 beats per minute during a brisk walk and 123 to 149 during a hard run. If you’ve heard of Zone 2 training, the aerobic zone that’s popular for building endurance and metabolic health, that corresponds to 60% to 70% of your maximum heart rate.
The Basic Calculation
The simplest approach multiplies your max heart rate by the low and high end of your target range. Here’s a worked example for a 50-year-old aiming for moderate intensity:
Maximum heart rate: 220 minus 50 = 170. Lower target: 170 times 0.50 = 85 bpm. Upper target: 170 times 0.70 = 119 bpm. Target zone: 85 to 119 beats per minute.
This percentage-of-max method is fast and easy. Its weakness is that it ignores your individual fitness level entirely. Two 50-year-olds with the same max heart rate but different resting heart rates could be at very different levels of actual effort while hitting the same number.
The Karvonen Method (More Personalized)
The Karvonen formula, also called the heart rate reserve method, accounts for your resting heart rate to give a more individualized target. Heart rate reserve is simply your max minus your resting rate. It represents the range your heart has to work with between rest and all-out effort.
The steps for a 50-year-old with a resting heart rate of 68, aiming for 60% to 80% intensity:
Maximum heart rate: 220 minus 50 = 170. Heart rate reserve: 170 minus 68 = 102. Lower target: 102 times 0.60 = 61.2, plus 68 = 129 bpm. Upper target: 102 times 0.80 = 81.6, plus 68 = 150 bpm. Target zone: 129 to 150 beats per minute.
Notice how much higher these numbers are compared to the basic method. That’s because the Karvonen formula recognizes that a person with a low resting heart rate has more cardiovascular headroom. Cardiac rehabilitation programs commonly use this method, prescribing 60% to 80% of heart rate reserve plus resting heart rate as the training target.
How Beta-Blockers Change the Math
If you take medication that lowers your heart rate (beta-blockers are the most common example), standard formulas will overestimate your actual max. Your heart simply can’t reach the predicted number while the medication is active. Research in the European Journal of Preventive Cardiology recommends that people on beta-blockers use slightly lower intensity thresholds: roughly 60% of heart rate reserve with the Karvonen method, or about 80% of their observed maximum, rather than the standard 70% or 85% targets. In practice, the most reliable approach is to have your max heart rate measured during a supervised exercise test rather than estimated by formula.
Checking Your Target Without a Monitor
If you don’t have a chest strap or wrist sensor, you can cross-check your effort using the Borg Rating of Perceived Exertion scale, which runs from 6 to 20. The original design was built around the idea that multiplying your RPE score by 10 roughly estimates your heart rate. So if your effort feels like a 14 on the scale (somewhat hard), your heart rate is likely around 140 bpm. This correlation holds reasonably well during progressively increasing workloads, with studies showing correlations between 0.71 and 0.91. It becomes less reliable during sustained all-out effort or near exhaustion, but for steady-state cardio, it’s a useful gut check.
The talk test works as a simpler alternative. If you can speak in full sentences but couldn’t sing, you’re in the moderate zone. If you can only get out a few words between breaths, you’ve crossed into vigorous territory.
Which Formula Should You Use
For general fitness purposes, the basic 220-minus-age formula multiplied by your target percentage is perfectly fine. If you want better accuracy, especially if you’re over 40, switch to the Tanaka formula (208 minus 0.7 times your age). Women get a more tailored estimate from the Gulati formula (206 minus 88% of age). And if you want to account for your personal fitness level, layer in the Karvonen method using heart rate reserve.
No formula is perfect. All of them are population averages applied to an individual, and your true max could sit 10 or more beats above or below the estimate. The formulas give you a starting range. From there, pay attention to how you feel, track your numbers over time, and adjust. If you’re hitting your calculated target but barely breaking a sweat, your actual max is likely higher than the formula predicted.