❤️ Target Heart Rate Calculator
Find your ideal heart rate zones for exercise based on your age
Heart Rate Zones Visualization
Zone 1 — Very Light
Warm-up, recovery, and cool-down. Improves overall health and aids fat metabolism.
Zone 2 — Light
Fat-burning zone. Builds basic endurance and aerobic base. Comfortable conversation pace.
Zone 3 — Moderate
Aerobic / cardio zone. Strengthens heart and lungs. Ideal for steady-state cardio workouts.
Zone 4 — Hard
Anaerobic zone. Improves speed, power, and lactate threshold. Breathing becomes heavy.
Zone 5 — Maximum
Peak effort. Sprinting and maximum performance. Sustain only for very short bursts.
⚠️ Disclaimer: This chart provides estimates based on the formula 220 − age. Individual maximum heart rates may vary. Consult your doctor before starting any new exercise program.
How to Use This Target Heart Rate Calculator
Finding your ideal exercise heart rate takes just 30 seconds with this calculator. Here’s exactly how to get accurate results:
- Enter your age — this is the only required input for a basic calculation.
- Add your resting heart rate (optional but recommended) — this unlocks the more accurate Karvonen method. Measure your pulse for 60 seconds first thing in the morning before getting out of bed.
- Choose your preferred formula — Haskell & Fox (220 − age) is the classic choice, while Tanaka or Gellish formulas give better accuracy for adults over 40.
- Read your five personalized heart rate zones — each zone shows the beats per minute (bpm) range you should aim for during different types of workouts.
The calculator instantly displays your maximum heart rate, heart rate reserve, and all five training zones in beats per minute. You can copy these numbers to your fitness tracker or smartwatch and start training smarter immediately.
What Is Target Heart Rate?
Target heart rate is the optimal beats-per-minute range your heart should reach during exercise to get the specific fitness benefit you’re after — whether that’s burning fat, building endurance, or improving VO2 max. Staying inside this range means your workout is intense enough to challenge your body but not so extreme that you risk injury or burnout.
Think of it as a personalized speedometer for your heart. Drive too slow and you waste your workout. Drive too fast and you crash. Your target heart rate is the sweet spot where every minute of exercise delivers measurable cardiovascular gains.
The American Heart Association recommends exercising between 50% and 85% of your maximum heart rate for healthy adults. But this single range hides a much more useful truth: different intensities inside that band produce dramatically different results, which is why the calculator above breaks your output into five distinct training zones.
Maximum Heart Rate (MHR) Explained
Your maximum heart rate is the absolute highest number of times your heart can beat in one minute during peak physical exertion. It’s the foundation that every target heart rate calculation is built on. Maximum heart rate is largely determined by age and genetics — training and fitness level have surprisingly little effect on it.
The theoretical ceiling for any human heart is around 300 bpm, but real-world maximum heart rates almost always fall between 160 and 220 bpm in healthy adults.
How to Measure Your MHR Accurately
The gold-standard method is a cardiac stress test, performed in a clinic while you’re hooked up to an electrocardiogram (ECG). You walk or run on a treadmill while a technician gradually increases the intensity until specific changes in your heart’s electrical activity confirm you’ve hit your true maximum. This is the only way to know your real number.
For everyone else, age-based formulas give a reasonable estimate — but they’re estimates, not facts. A famous study by Dr. Fritz Hagerman found that elite Olympic rowers in their 20s had maximum heart rates ranging from 160 to 220 bpm. That’s a 60-bpm spread among men of identical age and fitness level, which shows just how much individual variation exists.
Age-Based MHR Formulas (Compared)
The calculator above lets you choose between four scientifically validated formulas. Here’s how they differ:
| Formula | Equation | Best For |
|---|---|---|
| Haskell & Fox (1971) | MHR = 220 − age | Quick estimates, general population |
| Tanaka, Monahan & Seals (2001) | MHR = 208 − (0.7 × age) | More accurate for adults over 40 |
| Gellish (2007) | MHR = 206.9 − (0.67 × age) | Clinical settings, cardiac rehab |
| Nes, Janszky, Wisloff (2013) | MHR = 211 − (0.64 × age) | Healthy adults aged 19–89 |
The classic “220 minus your age” formula is the most famous, but research shows it can be off by 10–12 bpm for any individual. The Tanaka and Gellish formulas typically produce more accurate results for older adults because they decline less steeply with age.
Resting Heart Rate (RHR)
Resting heart rate is how many times your heart beats per minute when you’re completely at rest — awake, calm, comfortable, and not stressed or surprised. It’s one of the simplest yet most powerful indicators of cardiovascular health you can measure at home.
A healthy adult resting heart rate falls between 50 and 90 bpm. Older guidelines list 60–100 bpm, but updated research suggests the lower range better reflects modern cardiovascular benchmarks. Trained endurance athletes often have resting heart rates in the 40s, and elite cyclists like Miguel Indurain have recorded RHRs in the high 20s.
How to Measure Your Resting Heart Rate
For the most accurate reading, take your pulse first thing in the morning before getting out of bed. Place two fingers on your wrist (radial artery) or the side of your neck (carotid artery), count the beats for a full 60 seconds, and that’s your RHR. Wearable devices like Fitbit, Garmin, and Apple Watch automate this and average it over the entire night.
Tachycardia vs Bradycardia — When to See a Doctor
A resting heart rate consistently above 90 bpm is called tachycardia and may indicate dehydration, stress, anemia, thyroid problems, or heart disease. A resting heart rate below 50 bpm is called bradycardia — this is normal and even healthy in trained athletes, but in non-athletes it can signal heart block, hypothyroidism, or medication side effects. If your RHR is unusually high or low and you’re not an endurance athlete, talk to your doctor.
Heart Rate Reserve (HRR) — The Karvonen Foundation
Heart rate reserve is the difference between your maximum heart rate and your resting heart rate. It represents the actual “working room” your heart has available during exercise — and it’s the basis of the most accurate target heart rate method ever developed.
HRR = MHR − RHR
For example, a 36-year-old with a maximum heart rate of 184 and a resting heart rate of 70 has a heart rate reserve of 184 − 70 = 114 bpm. That 114 bpm represents the full range of intensity their heart can deliver above its baseline.
Why does this matter? A 25-year-old elite runner and a 25-year-old sedentary person can have the same maximum heart rate but very different resting heart rates. Heart rate reserve captures this fitness difference, which is why it produces personalized zones rather than one-size-fits-all numbers.
Karvonen Formula — The Most Accurate Method
The Karvonen formula, developed by Finnish physiologist Martti Karvonen in 1957, is widely considered the gold standard for calculating target heart rate. It accounts for both your maximum heart rate and your resting heart rate, producing zones that reflect your actual fitness level rather than just your age.
Target Heart Rate = [(MHR − RHR) × % Intensity] + RHR
Worked example: Let’s calculate a 70–80% target zone for a 36-year-old with a resting heart rate of 70 bpm.
- Step 1: MHR = 220 − 36 = 184 bpm
- Step 2: HRR = 184 − 70 = 114 bpm
- Step 3 (lower bound): (114 × 0.70) + 70 = 150 bpm
- Step 4 (upper bound): (114 × 0.80) + 70 = 161 bpm
Result: This person’s 70–80% Karvonen target zone is 150–161 bpm.
Compare this to the basic age formula (which would give 129–147 bpm) and you can see why Karvonen produces tougher, more accurate zones — it’s because a fitter person with a lower resting heart rate genuinely needs a higher exercise heart rate to reach the same training stimulus.
The 5 Target Heart Rate Zones
Modern exercise science divides target heart rate into five distinct zones, each delivering unique physiological benefits. The calculator above shows your personal numbers for all five — here’s what each one is actually doing inside your body.
Zone 1 — Warm Up Zone (50–60% MHR)
This is your easy, conversational pace. You can chat in full sentences without breathing hard. Zone 1 is perfect for warm-ups, cool-downs, active recovery days, and beginners just starting their fitness journey. It improves circulation, prepares your muscles for harder work, and helps clear lactate after intense sessions.
Zone 2 — Fat Burn Zone (60–70% MHR)
Despite the name, Zone 2 doesn’t burn the most total fat — but it burns the highest percentage of fat relative to carbohydrates. More importantly, Zone 2 builds your aerobic base, increases mitochondrial density, and improves your body’s ability to use fat as fuel during longer activities. You can still hold a conversation here, just with shorter sentences. Most endurance athletes spend 80% of their training in Zone 2.
Zone 3 — Aerobic / Cardio Zone (70–80% MHR)
This is the classic “cardio” zone. Breathing becomes deeper, talking gets harder, and your cardiovascular system is working hard to supply oxygen to your muscles. Zone 3 builds aerobic capacity, strengthens the heart muscle, and improves your sustainable pace. This is the zone most fitness apps recommend for general health benefits.
Zone 4 — Anaerobic Threshold Zone (80–90% MHR)
Now you’re working hard. Talking is reduced to short phrases, and lactate starts accumulating faster than your body can clear it. Zone 4 training raises your lactate threshold — meaning you can sustain harder paces for longer before fatiguing. This zone is the bread and butter of HIIT workouts and competitive endurance training.
Zone 5 — VO2 Max / Maximum Zone (90–100% MHR)
This is all-out effort, sustainable for only short bursts of 30 seconds to a few minutes at most. Zone 5 develops maximum oxygen uptake (VO2 max), neuromuscular power, and peak athletic performance. It should make up only a small fraction of your weekly training because the recovery cost is significant. This zone is reserved for sprint intervals, race finishes, and elite-level conditioning.
Target Heart Rate Chart by Age (Quick Reference)
Use this pre-calculated chart for instant target heart rate ranges based on the standard 220 − age formula. For more accurate numbers tailored to your fitness level, use the calculator above with your resting heart rate.
| Age | Max HR (bpm) | Zone 1 (50–60%) | Zone 2 (60–70%) | Zone 3 (70–80%) | Zone 4 (80–90%) | Zone 5 (90–100%) |
|---|---|---|---|---|---|---|
| 20 | 200 | 100–120 | 120–140 | 140–160 | 160–180 | 180–200 |
| 25 | 195 | 98–117 | 117–137 | 137–156 | 156–176 | 176–195 |
| 30 | 190 | 95–114 | 114–133 | 133–152 | 152–171 | 171–190 |
| 35 | 185 | 93–111 | 111–130 | 130–148 | 148–167 | 167–185 |
| 40 | 180 | 90–108 | 108–126 | 126–144 | 144–162 | 162–180 |
| 45 | 175 | 88–105 | 105–123 | 123–140 | 140–158 | 158–175 |
| 50 | 170 | 85–102 | 102–119 | 119–136 | 136–153 | 153–170 |
| 55 | 165 | 83–99 | 99–116 | 116–132 | 132–149 | 149–165 |
| 60 | 160 | 80–96 | 96–112 | 112–128 | 128–144 | 144–160 |
| 65 | 155 | 78–93 | 93–109 | 109–124 | 124–140 | 140–155 |
| 70 | 150 | 75–90 | 90–105 | 105–120 | 120–135 | 135–150 |
| 75 | 145 | 73–87 | 87–102 | 102–116 | 116–131 | 131–145 |
| 80 | 140 | 70–84 | 84–98 | 98–112 | 112–126 | 126–140 |
Rating of Perceived Exertion (RPE) — When You Don’t Have a Heart Rate Monitor
Rating of perceived exertion is a simple, equipment-free way to measure exercise intensity. Developed by Swedish psychologist Gunnar Borg, it asks you to rate how hard you feel you’re working on a numbered scale. Studies consistently show that RPE correlates strongly with measured heart rate, lactate levels, and oxygen consumption — meaning you can train effectively without any technology at all.
Original Borg Scale (6–20)
The original Borg scale runs from 6 (no exertion at all) to 20 (maximum effort). The clever design: multiply any number on the scale by 10, and you get an approximate heart rate.
| RPE | Intensity Description |
|---|---|
| 6 | No exertion at all |
| 7–8 | Extremely light |
| 9–10 | Very light |
| 11–12 | Light to moderate |
| 13–14 | Somewhat hard |
| 15–16 | Hard |
| 17–18 | Very hard |
| 19 | Extremely hard |
| 20 | Maximal exertion |
Modified Borg CR10 Scale (0–10)
The Borg CR10 scale is an easier 0-to-10 version, often used in clinical and rehab settings.
| CR10 | Intensity Description |
|---|---|
| 0 | No exertion |
| 0.5 | Just noticeable |
| 1 | Very light |
| 2 | Light |
| 3 | Moderate |
| 4 | Somewhat difficult |
| 5–6 | Difficult |
| 7–8 | Very difficult |
| 9 | Almost maximal |
| 10 | Maximal |
RPE is especially valuable for people on heart-rate-altering medications, in cardiac rehabilitation programs, or in pool-based exercise where heart rate responses change. The American College of Sports Medicine recommends RPE alongside heart rate as a standard intensity marker.
How Medications Affect Your Target Heart Rate
If you take certain medications, your heart rate response to exercise can change dramatically — and standard target heart rate formulas may give misleading results.
- Beta-blockers (atenolol, metoprolol, propranolol) lower both your resting and exercise heart rate. Someone on beta-blockers may never reach the heart rate their age formula predicts, even at maximum effort. Use RPE-based intensity (Borg scale) instead.
- Nitrates can raise resting heart rate slightly and may not change exercise heart rate predictably.
- Calcium channel blockers can blunt heart rate response similarly to beta-blockers.
- Stimulants (including caffeine, decongestants, and ADHD medications) can elevate resting heart rate and shift your zones upward.
If you’re on any cardiovascular medication, talk to your doctor or cardiac rehab specialist before relying on heart-rate-based training zones. RPE is almost always a safer, more reliable guide.
American Heart Association Guidelines
The American Heart Association (AHA) recommends that healthy adults exercise at 50% to 85% of their maximum heart rate for cardiovascular benefit. They define moderate-intensity activity as 50–70% of MHR (brisk walking, leisurely cycling, water aerobics) and vigorous-intensity activity as 70–85% of MHR (running, fast cycling, lap swimming, singles tennis).
The AHA’s broader physical activity guideline is 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic activity per week — or any equivalent combination. Pairing this duration target with the right heart rate zone is what unlocks real cardiovascular adaptation.
Common Mistakes When Calculating Target Heart Rate
Avoid these errors that quietly sabotage thousands of workout plans:
- Trusting “220 − age” as gospel. It has a standard error of roughly ±10–12 bpm. Use it as a starting point, not a finish line.
- Skipping your resting heart rate. Without it, you can’t use the more accurate Karvonen method, and your zones may be off by 10–15 bpm.
- Measuring resting heart rate after coffee or stress. Always measure first thing in the morning, in bed, before any caffeine or activity.
- Ignoring medications. Beta-blockers especially can make your “real” maximum heart rate 20–40 bpm lower than predicted.
- Confusing the fat-burn zone with the best fat-loss zone. Total calorie burn matters more than the percentage of calories from fat. Higher zones burn more total calories, including more fat in absolute terms.
- Never updating your numbers. Recalculate every 6–12 months as your fitness changes, especially as your resting heart rate drops.
Frequently Asked Questions
What is a good target heart rate for my age?
For most healthy adults, a good general target heart rate during moderate exercise is 50–70% of your maximum heart rate, and 70–85% during vigorous exercise. For a 40-year-old, that translates to roughly 90–126 bpm for moderate workouts and 126–153 bpm for vigorous ones. Use the calculator above for your exact personalized numbers.
Is the 220 minus age formula accurate?
Not really. The Haskell & Fox formula (220 − age) is widely used because it’s simple, but research shows it has a standard error of about ±10–12 bpm — meaning your actual maximum heart rate could be 10 beats higher or lower than the formula predicts. Newer formulas like Tanaka (208 − 0.7 × age) and Gellish (206.9 − 0.67 × age) are more accurate, especially for adults over 40.
What heart rate zone burns the most fat?
In terms of percentage of calories from fat, Zone 2 (60–70% MHR) burns the highest proportion of fat. But in terms of total fat calories burned per minute, Zone 3 and Zone 4 actually burn more — because you’re burning more total calories. The best zone for fat loss depends on your goal: Zone 2 builds aerobic base for sustainable fat-burning, while higher zones burn more total calories per session.
Should I use the Karvonen formula or the basic formula?
Use the Karvonen formula whenever you know your resting heart rate. It accounts for your individual fitness level and produces zones that scale with your actual cardiovascular health. The basic formula (a simple percentage of MHR) is fine for quick estimates, but it can underestimate the heart rates needed by fit people.
How do I measure my resting heart rate accurately?
Measure first thing in the morning, before getting out of bed and before any caffeine. Place two fingers on your wrist or neck, count the beats for a full 60 seconds, and repeat for three days to get a reliable average. Wearable devices like Fitbit, Apple Watch, Garmin, and Whoop track this automatically every night — these devices typically give very accurate readings.
What is a dangerous heart rate during exercise?
Sustained exercise above 100% of your predicted maximum heart rate can be a warning sign, especially if accompanied by chest pain, dizziness, nausea, or extreme shortness of breath. Anyone with known heart disease should stop exercising and seek medical attention if their heart rate behaves unexpectedly. For healthy adults, briefly hitting Zone 5 during sprints is normal and safe.
Does target heart rate differ for men and women?
The standard formulas treat men and women the same, but research suggests women may have slightly different maximum heart rate responses. The Gulati formula (206 − 0.88 × age) was specifically developed for women and tends to give slightly lower MHR estimates than 220 − age. For most practical purposes, the difference is small.
How does fitness level affect target heart rate?
Fitness barely changes your maximum heart rate, but it dramatically lowers your resting heart rate — which is why the Karvonen formula gives you very different zones than the basic formula as you get fitter. A trained athlete with an RHR of 45 bpm and an untrained person with an RHR of 75 bpm will have completely different target zones, even at the same age.
Can I exercise above my target heart rate zone?
Yes, briefly and intentionally. Zone 5 (90–100% MHR) is supposed to be above your normal training zone — that’s the point of high-intensity interval training. The issue is sustained exercise above your maximum heart rate, which signals you need to slow down. Brief surges into Zone 5 during HIIT, hills, or sprint intervals are not only safe but highly beneficial.
How often should I recalculate my target heart rate?
Recalculate every 6–12 months, or any time your resting heart rate changes by more than 5 bpm. As you get fitter, your RHR drops and your Karvonen zones shift upward. Updating your numbers ensures you keep training at the right intensity instead of accidentally getting too easy as your fitness improves.
References & Trusted Sources
- American Heart Association — Target Heart Rates Chart (heart.org)
- American College of Sports Medicine (ACSM) — Guidelines for Exercise Testing and Prescription
- Karvonen, M. J. (1957) — Original heart rate reserve methodology, Annales Medicinae Experimentalis et Biologiae Fenniae
- Tanaka, H., Monahan, K. D., Seals, D. R. (2001) — Age-predicted maximal heart rate revisited, Journal of the American College of Cardiology
- Gellish, R. L. et al. (2007) — Longitudinal modeling of the relationship between age and maximal heart rate, Medicine & Science in Sports & Exercise
- Nes, B. M., Janszky, I., Wisloff, U., Stoylen, A., Karlsen, T. (2013) — Age-predicted maximal heart rate in healthy subjects: The HUNT Fitness Study