What is a heart rate calculator?
A heart rate calculator uses your age and resting pulse to work out your maximum heart rate and the target heart rate zones for exercise. This free online heart rate calculator gives you the classic 220 − age estimate, the more accurate Tanaka formula, your heart rate reserve and five training zones calculated with the Karvonen method. Use the zones to run, cycle or do cardio at the right intensity – easy enough to burn fat in zone 2, or hard enough to improve speed.
What is heart rate?
Heart rate is the number of times your heart beats per minute (bpm). Your pulse rate is the same number felt at the wrist or neck, so for most healthy people heart rate and pulse rate are equal. A normal resting heart rate for adults is 60–100 bpm. Well-trained athletes often sit at 40–60 bpm because their heart pumps more blood with each beat.
How to use this heart rate calculator
- Enter your age in years.
- Measure your resting heart rate: in the morning, before getting out of bed, count your pulse for 60 seconds (or 30 seconds × 2). Average three mornings.
- Choose a max heart rate formula, or enter your real maximum if you have measured it in a supervised test.
The calculator shows your maximum heart rate, heart rate reserve and a zone table with both Karvonen targets and simple percentage-of-max targets.
Heart rate calculator formula
Maximum heart rate by age
Max HR (classic) = 220 − age
Max HR (Tanaka) = 208 − 0.7 × age
The 220 − age rule is easy to remember but tends to underestimate max heart rate for people over 40. The Tanaka formula (2001), based on data from more than 18,000 adults, is more accurate across ages. Both are averages – individuals can differ by 10 or more beats.
Karvonen formula (heart rate reserve)
Target HR = resting HR + (max HR − resting HR) × intensity %
- resting HR = your heart rate at complete rest
- max HR − resting HR = your heart rate reserve (HRR)
- intensity % = the zone percentage, e.g. 60% to 70% for zone 2
Because the Karvonen heart rate zone calculator includes your resting pulse, it adjusts for fitness: two people of the same age get different zones if one has a resting heart rate of 55 and the other 80.
Worked example
A 30-year-old with a resting heart rate of 70 bpm: max HR = 220 − 30 = 190 bpm (Tanaka gives 208 − 21 = 187 bpm). Heart rate reserve = 190 − 70 = 120. Zone 2 at 60–70% = 70 + 120 × 0.6 to 70 + 120 × 0.7 = 142–154 bpm. Zone 4 at 80–90% = 166–178 bpm.
Heart rate zones explained
| Zone | % of HRR | Feels like | Benefit |
|---|---|---|---|
| Zone 1 | 50–60% | Very easy, can chat freely | Warm-up, recovery, beginners |
| Zone 2 | 60–70% | Easy, can talk in sentences | Fat burning, aerobic base, heart health |
| Zone 3 | 70–80% | Moderate, short sentences | Aerobic fitness and endurance |
| Zone 4 | 80–90% | Hard, a few words only | Lactate threshold, race pace |
| Zone 5 | 90–100% | All-out | Speed and VO2 max intervals |
Heart rate for fat burning and weight loss
The so-called fat-burning zone is zone 2 (roughly 60–70% of heart rate reserve). At this intensity your body gets a larger share of its energy from fat, and you can keep going for 45–90 minutes. For weight loss, though, total calories burned matter most; mixing long zone 2 sessions with one or two harder interval sessions a week works well. See how many calories an activity burns with the calories burned calculator, and set your food intake with the TDEE calculator.
Heart rate calculator for running
Most running plans, including popular ones based on Joe Friel's or Garmin's zones, follow the same idea: about 80% of weekly running in zones 1–2 and 20% in zones 4–5. If your easy runs keep drifting into zone 3, slow down – building an aerobic base in zone 2 makes you faster over time. A chest strap measures heart rate more accurately than a wrist watch during intervals.
What should my heart rate be during exercise?
The American Heart Association suggests moderate exercise at about 50–70% and vigorous exercise at about 70–85% of maximum. Guidelines recommend at least 150 minutes of moderate or 75 minutes of vigorous activity per week. If you take beta-blockers or have a heart condition, your zones may not apply – ask your doctor for a personal target.
How to calculate heart rate from an ECG
Doctors calculate heart rate on a standard ECG (25 mm/s paper) with simple rules: 300 ÷ number of large boxes between two R waves, or 1,500 ÷ number of small boxes. For an irregular rhythm such as atrial fibrillation, count the QRS complexes in a 6-second strip and multiply by 10. From the RR interval in seconds, heart rate = 60 ÷ RR.
Age, resting pulse, zones and goals: what to enter
Heart rate calculator by age
Your age alone gives your estimated maximum, so a heart rate calculator by age is all you need for a quick answer. You may see tools asking for age and weight, but weight does not change max heart rate, so this calculator leaves it out.
Adding your resting heart rate
Enter your resting pulse and the calculator switches to the Karvonen method, which works from your heart rate reserve (HRR = max minus resting). Zones built this way fit fitter people better than a plain percentage of max.
Your training zones
The table gives your max heart rate and all five zones in one place, including the zone 2 range many endurance plans are built on. Garmin watches use similar bands by default, so the heart rate zones from this calculator carry over to a Garmin. Joe Friel's zones are different: that heart rate zone system is based on your lactate threshold heart rate (LTHR), which you find from a 30-minute time trial rather than from a calculator.
Exercise, cardio and running
For general cardio, aim for zones 2–3 most of the time and add short zone 4–5 efforts once or twice a week. The heart rate targets during exercise are the same for running, cycling or rowing; see the running section above for a running plan.
Fat burning and weight loss
If your goal is to burn fat or lose weight, spend most sessions in zone 2, where the body uses a larger share of fat for fuel. Using the calculator's heart rate zones to lose weight helps, but weight loss still depends mainly on diet.
Calories
Does heart rate determine how many calories you burn? Partly: a higher heart rate means more oxygen used. A heart rate alone cannot give calories; to estimate calories burned the calculator also needs weight and time, which our calories burned calculator provides.
Women and kids
The same calculator formulas work for women and their heart rate, though some research suggests 206 − 0.88 × age gives a better estimate. Kids are different: a child's resting heart rate is higher, about 70–120 bpm.
Measuring by tapping or by pulse
A tap calculator counts heart rate beats as you tap along with your pulse. Without one, count your pulse for 15 seconds and multiply by 4; that is how to calculate heart rate from pulse.
Reading heart rate from an ECG
You do not need a special calculator to read heart rate in an ECG. On a regular ECG, the small boxes rule works like a calculator: heart rate = 1,500 ÷ the number of small boxes between two R waves. That is how to calculate heart rate from rr interval spacing on an ECG graph. For an irregular ECG, such as atrial fibrillation, use the 6-second method: count the R waves in a 6-second strip and multiply by 10.
Formula, equation and key terms
The heart rate calculator formula and equation are shown above. What is heart rate reserve? Max minus resting. What is heart rate bpm? Beats per minute. What is heart rate variability? The small changes in time between beats, a sign of recovery.
This online calculator is free to use. Example from the max heart rate calculator: a 35 year old male gets 185 bpm (220 − 35) and a 43 year old male gets 177 bpm.
Heart rate intensity calculator: what should my heart rate be
The answer depends on what you are doing. At rest, 60–100 bpm is normal for adults. During exercise, this heart rate intensity calculator turns a percentage of your heart rate reserve into a target: 50–60% is easy, 60–70% is zone 2, 70–80% is moderate, 80–90% is hard and 90–100% is a near-maximal effort.
Heart rate jogging calculator
Easy jogging usually sits in zone 2 or low zone 3, about 60–75% of heart rate reserve. For a 40-year-old with a resting rate of 65 bpm (max 180 by 220 − age), that is roughly 134–151 bpm. If you cannot speak in full sentences, you are jogging harder than zone 2.
Heart rate limit calculator
Your upper heart rate limit for training is your maximum heart rate. Most healthy people should keep sustained efforts below 90% of it. If you have a heart condition or take beta-blockers, ask your doctor for a personal heart rate limit, because age formulas do not apply to you.
Heart rate interval calculator: RR interval to bpm
The RR interval is the time between two heartbeats on an ECG. A heart rate calculator from the RR interval uses one formula: heart rate = 60 ÷ RR interval in seconds, or 60,000 ÷ RR in milliseconds. An RR interval of 0.8 s gives 75 bpm; 1.0 s gives 60 bpm; 0.5 s gives 120 bpm.
Heart rate variability calculator
Heart rate variability (HRV) measures how much the RR intervals change from beat to beat. A common measure, RMSSD, is the square root of the mean of the squared differences between consecutive RR intervals. For intervals of 800, 820 and 790 ms, the differences are 20 and −30 ms, so RMSSD = √((400 + 900) ÷ 2) ≈ 25.5 ms. Higher HRV at rest usually means better recovery; compare your own trend rather than other people's numbers.
Heart rate calculator systolic and diastolic: not the same thing
Systolic and diastolic numbers are blood pressure, not heart rate. A reading such as 120/80 mmHg is pressure; the pulse your blood pressure machine shows next to it is heart rate in bpm. You cannot calculate heart rate from systolic and diastolic values.
Heart rate calculator machine, device, app or website?
- Machine or device: chest-strap monitors are the most accurate during exercise; wrist watches are good at rest and in steady efforts; pulse oximeters and blood pressure machines also show bpm.
- Heart rate calculator on phone: camera-based phone apps estimate pulse from your fingertip. They work at rest but are not medical devices.
- Heart rate calculator app or website: this page works in any phone browser, so you do not need an app to find your zones. Measure your pulse with a device, then enter it here.
Heart rate calculation questions with answers
- A 50-year-old has a resting rate of 60. What is 70% intensity? Max = 170, reserve = 110, target = 60 + 0.7 × 110 = 137 bpm.
- You count 18 beats in 15 seconds. What is your heart rate? 18 × 4 = 72 bpm.
- On an ECG at 25 mm/s, there are 4 large boxes between R waves. Heart rate = 300 ÷ 4 = 75 bpm.
Frequently asked questions
How is maximum heart rate calculated?
The classic formula is 220 minus your age. The Tanaka formula, 208 − 0.7 × age, is more accurate for adults over 40. A supervised exercise test gives your true maximum.
What is the heart rate zone 2 for my age?
Zone 2 is 60–70% of your heart rate reserve. For a 30-year-old with a resting heart rate of 70, it is about 142–154 bpm. Enter your details for your exact range.
What is a normal resting heart rate?
For adults, 60–100 bpm is normal. Fit people and athletes often have 40–60 bpm. A resting rate regularly above 100 bpm should be checked by a doctor.
What is the Karvonen formula?
Target heart rate = resting heart rate + (maximum heart rate − resting heart rate) × intensity. It uses your heart rate reserve, so it adapts to your fitness.
What heart rate burns the most fat?
Zone 2, about 60–70% of heart rate reserve, burns the highest proportion of fat. Harder exercise burns more total calories per minute.
What is the max heart rate for a 35-year-old male?
About 185 bpm by 220 − age, or 184 bpm by the Tanaka formula.
Is heart rate the same as pulse rate?
For most people, yes. Pulse rate is heart rate felt at an artery. They differ only in some heart rhythm problems.
How do I calculate heart rate from the RR interval?
Divide 60 by the RR interval in seconds. An RR interval of 0.75 s gives 80 bpm.
Can I calculate heart rate from blood pressure?
No. Systolic and diastolic values measure pressure. Your heart rate is the separate pulse number your monitor shows.
Last updated 2026-09-18