Skip to main content
Calculator Answers

Target Heart Rate Calculator

Source: 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 · Source verified July 22, 2026

Blake Boege
Written by Blake Boege · Founder, Calculator Answers

A target heart rate calculator is a fitness tool that estimates maximum heart rate and identifies heart rate zones for aerobic training. It applies formulas such as the standard age-based calculation or the Karvonen method, which incorporates resting heart rate. The resulting ranges correspond to different exercise intensity levels, from light activity to high-intensity cardiovascular effort. Athletes, trainers, and fitness enthusiasts use these outputs to structure exercise programmes and monitor performance.

Pick a method, enter your age (and resting HR for Karvonen). The calculator returns estimated maximum heart rate, AHA moderate and vigorous ranges, and Zone 1 to Zone 5 boundaries.

Quick Answer

Calculate your target training heart rate zones for different exercise intensities. Enter your age and resting heart rate to view maximum and target heart rate ranges.

years

e.g. 35

Estimated max HR uses 220 − age. Karvonen adds resting heart rate to give a more individualized target.

Target heart rate

Estimated max HR

185 bpm

Percent-of-max method

Moderate (AHA)93 to 130 bpm
Vigorous (AHA)130 to 157 bpm
Zone 1 (very light)93 to 111 bpm
Zone 2 (light)111 to 130 bpm
Zone 3 (moderate)130 to 148 bpm
Zone 4 (hard)148 to 167 bpm
Zone 5 (max)167 to 185 bpm

Estimates only. People with cardiac conditions, on rate-affecting medication (such as beta-blockers), pregnant, or with symptoms during exercise should ask a clinician before training to target zones.

Was this helpful?

Examples

Age 35, percent of max

max ≈ 185 · moderate 93 to 130 · vigorous 130 to 158

Age 50, percent of max

max ≈ 170 · moderate 85 to 119 · vigorous 119 to 145

Age 35, resting 65, Karvonen

reserve 120 · moderate 125 to 149 · vigorous 149 to 167

How it works

Formula · Target HR = ((HRmax − resting HR) × intensity %) + resting HR. The heart-rate reserve idea is Karvonen 1957; the rearrangement into a target and the 220 − age maximum are later convention and are not in that paper

The 5 heart rate training zones

Your maximum heart rate (220 minus your age) gets divided into five training zones, each with a different fitness benefit:

ZONE 1 — VERY LIGHT (50-60% of max HR): Recovery and warm-up zone. Easy to maintain conversation. Used for warm-ups, cool-downs, and recovery between hard workouts.

ZONE 2 — LIGHT / FAT BURNING (60-70% of max HR): Often called the 'fat burning zone' because the body uses a higher percentage of fat for fuel here. Sustainable for hours. Best for building aerobic base and endurance.

ZONE 3 — MODERATE / CARDIO (70-80% of max HR): The 'cardio zone.' Improves cardiovascular fitness and aerobic capacity. You can talk in short sentences but can't hold a long conversation. Sustainable for 30-60 minutes.

ZONE 4 — HARD / THRESHOLD (80-90% of max HR): Lactate threshold zone. Builds speed and improves your body's ability to clear lactic acid. Sustainable for 10-20 minutes. Used in interval training.

ZONE 5 — MAXIMUM / PEAK (90-100% of max HR): All-out effort. Builds VO2 max and explosive power. Sustainable for only 1-5 minutes per interval. Used in high-intensity interval training (HIIT).

How the math works

Max HR is estimated as 220 minus age. Zones are percentages of that max. Karvonen adds resting HR to the math, which personalizes the target ranges based on your starting fitness.

Max HR · HRmax ≈ 220 − age (convention, not Karvonen's)

Percent of max · target = intensity × HRmax

Karvonen · target = resting + intensity × (HRmax − resting)

AHA moderate ~50 to 70% · vigorous ~70 to 85%.

Fat burning vs. cardio zones

The 'fat burning zone' (Zone 2, 60-70% of max HR) does use a higher PERCENTAGE of fat for fuel, but it burns FEWER total calories per minute than the cardio zone. The misleading name comes from this percentage-vs-total confusion.

Example: A 30-year-old (max HR 190) in Zone 2 (133 bpm) might burn 8 calories/minute with 50% from fat = 4 fat calories/minute. The same person in Zone 3 (152 bpm) might burn 12 calories/minute with 35% from fat = 4.2 fat calories/minute — slightly MORE fat burning despite the lower percentage.

The truth: for fat loss, total calorie burn matters more than the 'fat burning percentage.' Higher-intensity workouts in Zone 3-4 typically burn more total fat per workout, plus they trigger excess post-exercise oxygen consumption (EPOC) which keeps your metabolism elevated for hours after.

When Zone 2 is best: Long-duration endurance training (1+ hour), recovery workouts, base-building for athletes, and beginners building aerobic capacity.

When higher zones are best: Time-limited workouts, fat loss focus, fitness improvement, and HIIT.

Karvonen formula vs. simple formula

There are two ways to calculate target heart rate:

SIMPLE METHOD: Target HR = Max HR × intensity percentage
Example: A 30-year-old at 70% intensity = (220-30) × 0.70 = 133 bpm

KARVONEN FORMULA (more accurate): Target HR = ((Max HR - Resting HR) × intensity %) + Resting HR
Example: A 30-year-old with resting HR of 65 at 70% intensity = ((190-65) × 0.70) + 65 = 152 bpm

The Karvonen formula accounts for your individual resting heart rate, which varies based on fitness level. A highly fit person with a low resting HR (40-50) gets a lower Karvonen target than someone with a higher resting HR (70-80) at the same intensity percentage. This is why Karvonen is preferred for trained athletes.

To find your resting heart rate: measure your pulse for 60 seconds first thing in the morning, before getting out of bed, for 3-5 consecutive days, and use the average. That is the figure this calculator wants. A pulse taken later in the day after sitting quietly is a different measurement and typically runs several beats higher, which narrows the heart-rate reserve and shifts every zone upward, so do not mix the two.

Related health calculators

Health note. Estimated zones are for planning use. People with cardiac conditions, on heart-rate-affecting medication (such as beta-blockers), pregnant, or with new exercise symptoms should talk to a clinician before training to target zones.

Related Calculators

More tools from Health

Heart Rate CalculatorFind your maximum heart rate, target heart rate zones, and fat-burn vs cardio zone ranges for exercise.

Frequently asked questions

The classic estimate is 220 minus your age, in beats per minute. So a 35-year-old has an estimated max HR around 185 bpm. This formula is widely used but is a population average; individual max HR can vary by 10 to 15 bpm.

Zones 1 to 5 split percentages of max HR. Zone 1 (very light) is 50 to 60%, Zone 2 (light) is 60 to 70%, Zone 3 (moderate) is 70 to 80%, Zone 4 (hard) is 80 to 90%, Zone 5 (max) is 90 to 100%. Different training plans use slightly different ranges, but the layout is standard.

Not to the arithmetic, and it is worth seeing because it shows the formula being reconstructed rather than copied. Karvonen's 1957 paper prints its intensity expression with the numerator as the working rate alone, WR over the range from resting to maximum. Taken literally that is wrong, and the paper's own data prove it: subject B.K. has a working rate of 136, a maximum of 192 and a resting rate of 52, and Table 1 gives the intensity as 60 per cent. As printed the expression gives 136 over 140, which is 97 per cent. Subtract the resting rate from the numerator as well, (136 − 52) over (192 − 52), and it is exactly 60. The Figure 1 caption checks the same way: a heart rate of 136 described as "71 per cent of the available range" is (136 − 52) over (170 − 52), which is 71.2. So the intended formula is the one this page computes, and the printed one is a typesetting error that survived into the journal.

Less than the formula named after him. The 1957 paper is six male medical students, aged 20 to 23, whose maximum heart rates were MEASURED by running them to exhaustion rather than estimated from age. What it concluded is a threshold: training heart rate "has to be more than 60 per cent of the available range from rest to the maximum attainable by running " in order to produce a training effect. That idea, intensity as a percentage of the range from rest to maximum rather than of the maximum alone, is genuinely Karvonen's and is what this page computes: target = resting + intensity × (maximum − resting). What is NOT in the paper is the rearrangement itself, which later writers derived, and the 220 minus age estimate this page feeds it. Karvonen published no age-prediction equation and told an interviewer in 2000 that he had never published original research on that formula at all. So treat the reserve idea as his and the two things wrapped around it as convention.

The American Heart Association suggests moderate intensity at roughly 50 to 70 percent of max HR and vigorous intensity at roughly 70 to 85 percent. Adults are advised to get at least 150 minutes of moderate activity, or 75 minutes of vigorous activity, per week.

It is a useful starting estimate, not a measurement. Individual max HR varies. More accurate values come from a supervised maximal exercise test. For everyday training, 220 minus age is fine; for performance training, a measured max may be worth getting.

Watches and apps may use different formulas (Tanaka 208 − 0.7×age, lab-tested max HR, lactate threshold zones) and different zone boundaries. If your device measures HR directly during workouts, you can refine zones over time from real data.

The simple estimate is 220 minus your age. So a 30-year-old has a max HR of ~190 bpm, a 50-year-old ~170 bpm, a 70-year-old ~150 bpm. This formula is an estimate — actual max HR varies by ±10-15 bpm between individuals. For a precise number, a supervised maximal exertion test at a sports medicine clinic is the gold standard.

Multiply your max HR (220 minus age) by 0.60 and 0.70 for the low and high ends of Zone 2. Example: a 35-year-old has max HR 185, so Zone 2 is 111-130 bpm. But remember — Zone 2 burns a higher percentage of fat, not necessarily more total fat. For maximum fat loss, total workout intensity and duration matter more.

No. Effective training mixes intensities across multiple zones. A typical week for an active adult: 1-2 easy Zone 1-2 sessions for recovery, 2-3 moderate Zone 3 sessions for cardio fitness, and 1-2 hard Zone 4-5 sessions (intervals or hill repeats) for improvement. Spending every workout at the same intensity leads to plateaus.

Briefly hitting Zone 5 (90-100% of max) is normal and safe for healthy people during intervals or hill efforts. Sustained heart rates above your estimated max for more than 5-10 minutes are unusual and worth checking with a doctor, especially if accompanied by chest pain, dizziness, or shortness of breath. People with heart conditions or on certain medications (beta-blockers) should consult a doctor for personalized zones.