Target Heart Rate Calculator
Find your max heart rate and 5 training zones using both simple (220 − age) and Karvonen formulas, alongside the moderate and vigorous ranges from MedlinePlus.
Reviewed & updated for 2026 by Rakesh Choudhary, PhDMethodology & sources · How we calculate
What each training zone does to your body
The only official ranges on this page are MedlinePlus's: 50% to 70% of your maximum heart rate for moderate-intensity exercise and 70% to 85% for vigorous exercise. For a 35-year-old that is 93 to 130 BPM and 130 to 157 BPM.
The five zones are a coaching convention layered on top, with no official definition. Zone 1 (50-60% of max) is easy recovery and warm-up pace. Zone 2 (60-70%) is steady, comfortable aerobic work. Zone 3 (70-80%) is a harder tempo you can still talk through in short phrases. Zone 4 (80-90%) is threshold work, usually done as intervals. Zone 5 (90-100%) is short, all-out effort.
Coaches differ on where the lines fall and how to split training time between zones. Treat the zone numbers as a rough guide, not a prescription.
Why 220 − age is only an estimate
MedlinePlus calls 220 minus your age an approximate maximum heart rate. It is a population average, usually credited to Fox, Naughton and Haskell (1971), and individuals vary around it. A 2024 review of target heart rate formulas notes that it tends to overestimate maximum heart rate in young adults and underestimate it in older adults. Tanaka's formula (208 − 0.7 × age), from a larger pooled analysis, is shown alongside for comparison; it is an estimate too.
The Karvonen formula uses heart rate reserve (HRR = max − resting) instead of a straight percentage of maximum, so two people of the same age with different resting rates get different zones. Target HR = (HRR × intensity %) + resting HR. For a 35-year-old with a resting rate of 65, 70% by Karvonen is ((185 − 65) × 0.70) + 65 = 149 BPM; 70% of maximum is 130 BPM. It is a published fitness formula; MedlinePlus's ranges use percentages of maximum.
Your actual maximum can only be measured in an exercise test. Talk to a doctor before any maximal-effort test, especially if you have a heart condition or take medicine that affects your heart rate.
The "fat burning zone" myth
Low-intensity exercise burns a higher percentage of its calories from fat than harder exercise does. That led to the "fat burning zone" labels on cardio machines. But harder exercise burns more calories per minute in total, so the amount of fat burned need not be lower, and the total energy used is higher.
For weight loss, the overall calorie deficit matters more than which fuel you burned during the session. The case for easier sessions isn't "more fat burn"; it's that you can keep them up for longer and recover faster, which lets you do more in a week.
FAQs
What is target heart rate?
The range of heartbeats per minute (BPM) to aim for during exercise. MedlinePlus puts moderate-intensity exercise at 50% to 70% of your maximum heart rate and vigorous exercise at 70% to 85%. The five zones in this calculator are a common coaching convention, not official guidance.
How is max heart rate calculated?
MedlinePlus: subtract your age from 220 for an approximate maximum, so 190 BPM for a 30-year-old. Tanaka and colleagues (2001) published 208 − 0.7 × age as an alternative: 208 − 21 = 187 BPM at 30. Both are population averages, and your own maximum can be well above or below either.
What's the Karvonen formula?
A published fitness formula that works from heart-rate reserve, your maximum minus your resting rate: target = ((max − resting) × intensity) + resting. Example: a 30-year-old (max 190) with a resting rate of 60, at 70%: ((190 − 60) × 0.70) + 60 = 151 BPM. MedlinePlus's ranges are plain percentages of maximum, so the two methods give different numbers for the same percentage.
What's a 'fat burning zone'?
Zone 2 in this calculator (60-70% of max) is often labelled "fat burn". At lower intensity a larger share of the calories you burn comes from fat, but you burn fewer calories in total than at higher intensity. For weight loss, total calories burned matter more than the share from fat, so the label is misleading.
How do I measure my heart rate?
MedlinePlus: find your pulse on the inside of your wrist below the base of the thumb, or on your neck beside your Adam's apple. Count the beats for 10 seconds and multiply by 6 to get beats per minute. For your resting rate, measure first thing in the morning before getting up. A heart rate monitor or fitness watch saves stopping to count.