Target Heart Rate Zone Calculator

How to calculate your target heart rate

A target heart rate is the range your heart should beat in during exercise to hit a chosen level of effort. Calculating it takes two steps. First, estimate your maximum heart rate — the highest your heart can beat during all-out exertion. Second, take a percentage of that maximum to mark the upper and lower edge of each training zone. An easy recovery walk might sit at 50 to 60 percent of maximum, while a hard interval pushes toward 90 percent and above.

The calculator above does both steps automatically. Enter your age and it estimates your maximum heart rate, then splits the range into five zones. If you also enter a resting heart rate, it switches to the Karvonen method, which is described further down and produces zones that better reflect your individual fitness.

Maximum heart rate formulas explained

Maximum heart rate cannot be looked up in a table with certainty; it can only be measured directly in a lab test or estimated from a formula. The most familiar estimate is 220 minus your age. It is simple and easy to remember, but it was never derived from rigorous research — it came from a casual fit to limited data in the 1970s and tends to overstate the maximum for younger people and understate it for older people.

This tool leads with a more accurate alternative: 211 minus 0.64 times your age. This formula comes from a large 2013 study published in the journal Medicine & Science in Sports & Exercise and fits a much broader, more representative population. For a 40-year-old it gives 185 beats per minute, compared with 180 from the classic formula. The gap widens with age, which is why older adults in particular benefit from the newer estimate.

Both numbers are still estimates. Real maximum heart rate varies widely between individuals of the same age — two healthy 50-year-olds can differ by 20 beats per minute or more. Treat the figure as a useful starting point for setting zones, not as a fixed ceiling. The calculator shows both formulas side by side so the difference is clear.

The five heart rate zones explained

Most training systems divide effort into five zones, each defined as a band of maximum heart rate (or of heart rate reserve when a resting heart rate is known). Each zone trains the body in a different way:

The zones overlap at their edges by design — 70 percent is both the top of Zone 2 and the bottom of Zone 3 — so treat the boundaries as soft transitions rather than hard walls. A balanced week usually mixes a lot of easy time in Zones 1 and 2 with smaller doses of the harder zones.

What is the fat-burning zone — and is it a myth?

The "fat-burning zone" is the lower-intensity band of roughly 60 to 70 percent of maximum heart rate, overlapping with Zone 2. The label is rooted in a real fact: at lower intensities, a higher percentage of the energy your body burns comes from fat rather than carbohydrate. That is true.

The myth is in how that fact gets used. Burning a higher percentage from fat is not the same as burning more total fat. Higher-intensity exercise burns far more calories per minute, so it often burns more total fat as well, even though a smaller share of that energy comes from fat. A relaxed 30-minute walk may draw 60 percent of its modest calorie total from fat; a hard 30-minute run burns many more calories and frequently more fat overall.

The practical takeaway is honest and simple: there is no single heart rate that magically melts fat. What drives fat loss is total energy burned over time, combined with eating habits. Lower zones are valuable because they are sustainable and easy to recover from, not because they unlock a special fat-burning switch.

What is Zone 2 and why it matters

Zone 2 is the easy, conversational effort at about 60 to 70 percent of maximum heart rate — the pace at which you could hold a chat without gasping. It has earned a large following among endurance athletes and coaches for good reason. Training here builds the body's aerobic base: it increases the density of mitochondria, improves how efficiently muscles use fat for fuel, and strengthens the heart's ability to pump blood, all with very little strain.

Because Zone 2 is low-stress, it can be sustained for long sessions and repeated often without the recovery cost of hard training. Many endurance plans deliberately spend the majority of weekly time in this zone, reserving only a small slice for high-intensity work. For general health, regular Zone 2 activity is one of the most efficient ways to improve cardiovascular fitness over time.

Using the Karvonen method with your resting heart rate

The simplest way to set zones is to take a flat percentage of maximum heart rate. The Karvonen method refines this by accounting for your resting heart rate, which reflects your fitness — a fitter heart beats fewer times at rest. Instead of working from maximum heart rate alone, Karvonen works from your heart rate reserve, the gap between your maximum and your resting heart rate.

The formula for each zone boundary is: target = ((maximum heart rate − resting heart rate) × intensity %) + resting heart rate. Because it adds your resting heart rate back in, the resulting zones sit a little higher and are tuned to you rather than to a population average. To use it well, measure your resting heart rate first thing in the morning before getting out of bed, ideally averaged over several days.

When the resting heart rate field above is left blank, the calculator falls back to the straightforward percentage-of-maximum method and labels the result accordingly. When a value is entered, it applies Karvonen automatically and notes that heart rate reserve was used.

Frequently asked questions