Your target heart rate is a specific range of beats per minute you aim for during exercise, and calculating it takes about 30 seconds once you know two numbers: your age and your resting heart rate. The most common approach uses a simple age-based formula to estimate your maximum heart rate, then applies a percentage based on how hard you want to work. Here’s how to do it step by step.
Step 1: Find Your Resting Heart Rate
Your resting heart rate is the number of times your heart beats per minute when you’re awake, calm, and not moving. The best time to measure it is first thing in the morning, before you get out of bed or drink coffee.
To take your pulse manually, turn one hand palm-up and place the tips of your index and middle fingers on the inside of your wrist, in the groove between the wrist bone and the tendon on the thumb side. Press lightly until you feel each beat. Count the beats for 60 seconds, or count for 15 seconds and multiply by four. You can also use the side of your neck: place two fingertips in the groove next to your windpipe on one side. Don’t press on both sides at once, and don’t push too hard. Light pressure is all you need.
For most healthy adults, resting heart rate falls between 60 and 100 beats per minute. If you use a fitness tracker or smartwatch, check its morning readings over several days and average them.
Step 2: Estimate Your Maximum Heart Rate
Your maximum heart rate is the fastest your heart can beat during all-out effort. You don’t need to actually push yourself that hard to find it. Two well-known formulas give you a reasonable estimate based on age alone.
The classic formula is 220 minus your age. A 40-year-old, for example, gets an estimated max of 180 beats per minute. This equation is everywhere because it’s easy to remember, but it has a significant margin of error. The standard deviation is about 11 beats per minute, meaning your true max could easily be 10 or more beats higher or lower than what the formula predicts.
A more refined formula, developed by researcher Hirofumi Tanaka, is 208 minus (0.7 × your age). For that same 40-year-old, this gives 180 as well, but the two formulas diverge more at younger and older ages. The Tanaka formula tends to be more accurate for older adults, where the classic formula often underestimates max heart rate. Cleveland Clinic references a similar alternative: 207 minus (0.7 × your age).
Neither formula is perfect. They’re population averages, not personal measurements. But for setting training zones, they’re a solid starting point.
Step 3: Calculate Your Target Range
There are two ways to turn your max heart rate into a target zone. The simpler method uses straight percentages of your max. The more personalized method, called the Karvonen method, factors in your resting heart rate.
The Percentage-of-Max Method
Multiply your estimated max heart rate by the lower and upper bounds of the intensity you want. The American Heart Association defines moderate-intensity exercise as 50% to 70% of your max and vigorous exercise as 70% to 85%.
For a 35-year-old with an estimated max of 185 (using 220 minus age):
- Moderate intensity (50% to 70%): 93 to 130 bpm
- Vigorous intensity (70% to 85%): 130 to 157 bpm
The Karvonen Method (Heart Rate Reserve)
This method accounts for your fitness level by incorporating resting heart rate. It’s more accurate for people whose resting heart rate is unusually low or high. The formula has three steps:
First, find your heart rate reserve: subtract your resting heart rate from your max heart rate. Then multiply that reserve by your desired intensity percentage. Finally, add your resting heart rate back.
For the same 35-year-old with a max of 185 and a resting heart rate of 65:
- Heart rate reserve: 185 minus 65 = 120
- Target at 60% intensity: (120 × 0.60) + 65 = 137 bpm
- Target at 80% intensity: (120 × 0.80) + 65 = 161 bpm
Notice how the Karvonen method produces higher target numbers than the straight percentage method at the same intensity level. That’s because it adjusts for your baseline fitness. Someone with a resting heart rate of 55 will get a different target than someone at 75, even if they’re the same age.
What Each Heart Rate Zone Does
Heart rate training zones are typically divided into five tiers, each with a different purpose:
- Zone 1 (50% to 60% of max): Very light effort. Good for warm-ups, cooldowns, and recovery days.
- Zone 2 (60% to 70% of max): Comfortable, conversational pace. This builds endurance and is the foundation of most aerobic training. Think brisk walking or easy jogging.
- Zone 3 (70% to 80% of max): Moderate effort that builds both strength and cardiovascular endurance. Breathing is heavier, but you can still speak in short sentences.
- Zone 4 (80% to 90% of max): Hard effort that improves speed and power. You can sustain this for shorter periods, typically 10 to 30 minutes.
- Zone 5 (90% to 100% of max): All-out effort. This strengthens your heart by forcing it to work at peak capacity and builds fast-twitch muscle fibers. Intervals in this zone last seconds to a few minutes.
Most general fitness goals are well served by spending the majority of your training time in Zones 2 and 3. If your goal is weight management or heart health, the American Heart Association’s recommendation of 50% to 85% of max covers Zones 2 through 4.
When the Formulas Don’t Work
Beta-blockers and certain other blood pressure medications slow your heart rate by design. If you take one, you may never reach your calculated target heart rate no matter how hard you push. The numbers simply won’t apply to you in the usual way.
In that case, a perceived exertion scale is more useful. The Borg Rating of Perceived Exertion Scale asks you to judge how hard you’re working based on your breathing, fatigue, and overall effort rather than a number on a monitor. A practical shortcut: if you can carry on a conversation during exercise, you’re in moderate territory. If you can’t talk at all, you’re likely working too hard for sustained effort.
The standard formulas can also be less reliable at the extremes of age. The 220-minus-age equation was developed from data skewed toward younger adults, and it tends to underestimate max heart rate in people over 50. If you’re in that group, the Tanaka formula (208 minus 0.7 times your age) is a better starting point.
Putting It All Together
If you want the quick version: subtract your age from 220, then multiply by 0.50 and 0.85 to get the lower and upper bounds of a general exercise target zone. If you want more precision, use the Karvonen method with your morning resting heart rate. Either way, treat the result as a guide rather than a hard rule. A standard deviation of 11 bpm on the max heart rate formula means your true zone could be a full 10 beats higher or lower.
A chest strap heart rate monitor will give you the most accurate real-time readings during exercise. Wrist-based optical sensors on smartwatches are convenient but can lag or misread during high-intensity intervals or activities with a lot of wrist movement. Whichever tool you use, checking in on your heart rate a few times per workout is enough to keep you in the right range without obsessing over every beat.