Target Heart Rate Calculator

Updated 2026-09-09

Your target heart rate is the range you aim for during exercise, set as a percentage of your maximum heart rate. The American Heart Association uses 50 to 70% of max for moderate exercise and 70 to 85% for vigorous. Enter your age to get your range for any goal, and add your resting heart rate for the personalized Karvonen version most watches use.

What "Target Heart Rate" Means

Target heart rate is the effort you are aiming for during a session, expressed in beats per minute. It exists because the same workout does very different things at different intensities: an easy hour and a set of hard four-minute intervals both raise fitness, but through different adaptations, and each has its own heart rate window. Pick the goal, and the target is the window that produces it.

The reference framing comes from the American Heart Association: moderate exercise is 50 to 70% of your maximum heart rate, vigorous is 70 to 85%. Those two bands cover general health. Athletes split the same span more finely into five zones, and the two that matter most sit at the ends: the easy aerobic base at 60 to 70%, and the VO2 max intervals at 90 to 95%.

How the Target Is Calculated

1. Percentage of max heart rate

The simple method: estimate your max with the Tanaka formula, 208 - (0.7 x age), validated across 18,712 subjects (Tanaka et al., 2001), then multiply by the intensity for your goal. A 40-year-old has a max of about 180 bpm, so a moderate target is roughly 90 to 126 bpm. If you have measured your real max, our max heart rate calculator compares all four formulas.

2. Karvonen (heart rate reserve)

Straight percentages ignore your resting heart rate. The Karvonen method (Karvonen et al., 1957) works from your reserve: target = (HRmax - HRrest) x intensity + HRrest. It sits higher than the plain percentage version and matches what most Garmin, Polar, and Apple Watch settings use, which is why your watch and a simple formula often disagree. Enter your resting heart rate above to switch the targets to this method.

Target Heart Rate by Goal

Using the Tanaka max estimate, the target ranges for a 40-year-old (max about 180 bpm):

Your own numbers depend on your age and, for the Karvonen version, your resting heart rate; the calculator above gives the exact ranges. Individual max heart rates spread about plus or minus 10 bpm around any age formula, so treat the estimate as a starting point and refine it with a measured max.

Using Your Target, and the 80/20 Rule

The most consistent finding in endurance research is how the intensities are distributed: analyses of elite training across aerobic sports find roughly 80% of sessions easy and 20% hard (Seiler, 2010). In practice that means most of your time sits in the moderate or fat-burn target, building the aerobic base, and one or two sessions a week reach the threshold or VO2 max target. The hard end is where the ceiling moves: four-minute intervals at 90 to 95% of max raised VO2 max 7.2% in eight weeks in a controlled trial (Helgerud et al., 2007).

The difficulty is holding the target once you have it, because heart rate drifts with fatigue, heat, and terrain. This is what PEAKVO2's guided sessions are for: your target range on screen and wrist for the whole session, with automatic phase changes, so the easy days stay easy and the hard intervals hit the right number.

Frequently Asked Questions

What is my target heart rate?

The range you aim for during exercise, as a percentage of your maximum heart rate. The American Heart Association uses 50 to 70% of max for moderate exercise and 70 to 85% for vigorous. For a 40-year-old with an estimated max of 180 bpm, that is about 90 to 126 bpm moderate and 126 to 153 bpm vigorous. The calculator above gives your exact ranges.

How do I calculate my target heart rate?

Estimate your max as 208 minus 0.7 times your age, then multiply by the intensity you want. For a more personal number, use the Karvonen method: target = (max HR minus resting HR) times intensity, plus resting HR. Enter your age and resting heart rate above and the calculator does both.

What is a good target heart rate to burn fat?

The largest share of calories from fat is burned at an easy 60 to 70% of max, the conversational zone 2 effort. But total calories, and total fat over time, are higher at harder efforts and with the afterburn from intervals, so fat loss depends far more on overall training volume and diet than on staying in one "fat-burning" zone.

Should I use max heart rate or heart rate reserve?

Heart rate reserve (Karvonen) is more personal and matches your watch, because it accounts for your resting heart rate. Plain percentage of max is simpler and fine when you do not know your resting rate. Enter your resting heart rate above to switch to the Karvonen targets.

What heart rate raises VO2 max?

Hard intervals at 90 to 95% of max drive the biggest gains. Four-minute intervals at that intensity, the Norwegian 4x4, raised VO2 max 7.2% in eight weeks in a controlled trial. Pick the VO2 max intervals goal above to see that range for your age, then estimate your current score with the VO2 max calculator.

References

1. Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol. 2001;37(1):153-156. PubMed
2. Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate; a longitudinal study. Ann Med Exp Biol Fenn. 1957;35(3):307-315. PubMed
3. Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? Int J Sports Physiol Perform. 2010;5(3):276-291. PubMed
4. Helgerud J, Høydal K, Wang E, et al. Aerobic high-intensity intervals improve VO2max more than moderate training. Med Sci Sports Exerc. 2007;39(4):665-671. PubMed