Target Heart Rate Calculator
Find the heart-rate range that matches the workout you want. Enter your age (and optionally your resting heart rate) to get your estimated max heart rate, a target at any intensity, and the full 50–85% zone table — by simple percent-of-max or the Karvonen heart-rate-reserve method.
How you compare
How target heart rate works
Your heart rate is the most practical live gauge of exercise intensity. Training inside a target range keeps a workout doing what you intend — easy days easy, hard days hard. The simple method takes a percentage of your estimated max heart rate. The Karvonen method instead scales your heart-rate reserve (max minus resting), then adds resting HR back, so two people of the same age with different fitness get different, more personal targets. Age formulas are population averages: real max heart rates vary by 10–20 bpm either way, so treat zones as guide rails, not laws.
How it’s calculated
Max HR is 220 − age (Haskell & Fox 1971), 208 − 0.7×age (Tanaka 2001), 211 − 0.64×age (Nes 2013), or your tested value. Percent-of-max target = MHR × intensity%. Karvonen target = (MHR − resting HR) × intensity% + resting HR. The zone table applies both formulas from 50% to 85%, the range the American Heart Association uses for moderate-to-vigorous exercise.
Estimates for healthy adults, not medical advice. If you have a heart condition, take rate-limiting medication (like beta blockers), are pregnant, or are starting exercise after a long break, ask a clinician for your safe range before training by these numbers.
Your zone table (50–85%)
Both methods shown; Karvonen uses the resting HR you entered (default 70 bpm).
Worked example
A 36-year-old has an estimated max of 220 − 36 = 184 bpm. At 70% intensity the percent-of-max target is 129 bpm; with a resting HR of 70, heart-rate reserve is 114, so the Karvonen target is 0.70 × 114 + 70 = 150 bpm. Their moderate 50–70% zone runs 92–129 bpm (percent-of-max) or 127–150 bpm (Karvonen); the vigorous 70–85% zone is 129–156 or 150–167 bpm.
Common mistakes
- Mixing methods — a “70% Karvonen” target is much higher than “70% of max,” so know which one your training plan means.
- Treating 220 − age as exact; individual max HR commonly differs from the formula by 10–20 bpm.
- Measuring resting HR after coffee, stress, or standing up — take it seated, relaxed, ideally on waking.
- Chasing zone 4–5 every session; most endurance plans put the bulk of weekly minutes below 70%.
Where it is used
- Setting watch or chest-strap zone alerts for easy runs, tempo work, and intervals.
- Cardiac-safe exercise prescriptions (with clinician-set ceilings).
- Fat-burn vs. cardio programming on gym equipment.
- Pacing long events where drift above threshold costs you later.
Frequently asked questions
What is the difference between percent-of-max and the Karvonen method?
Percent-of-max multiplies your maximum heart rate by an intensity percentage. The Karvonen method multiplies your heart-rate reserve (max minus resting) by the percentage, then adds resting HR back, so it personalizes the zone to your fitness. For a 36-year-old with a resting HR of 70, the 70% target is 129 bpm by percent-of-max but 150 bpm by Karvonen.
Which max heart rate formula is most accurate?
All age formulas are population averages with wide individual spread. 220 − age (Haskell & Fox) is the classic; Tanaka (208 − 0.7×age) and Nes (211 − 0.64×age) fit modern datasets somewhat better, especially past age 40. A measured max from a supervised stress test beats any formula.
What resting heart rate is normal?
The American Heart Association cites a typical adult resting heart rate of 60–100 bpm, and many fit adults sit in the 50s. Measure it after waking, before coffee. A resting HR persistently above 100 bpm, or an unexplained large change, is worth mentioning to a clinician.
Is training above 85% of max heart rate dangerous?
Short intervals near max are a normal part of training for healthy people, but the AHA target zones stop at 85% for general fitness because time above that adds strain faster than benefit. If you are new to exercise, older, pregnant, on heart medication, or have any cardiac history, get medical guidance before high-intensity work.
Do beta blockers or other medications change my zones?
Yes. Beta blockers lower both resting and maximum heart rate, so age-based formulas overstate your zones. Some stimulants and thyroid conditions push rates the other way. In these cases use perceived exertion or a clinician-set target instead of an age formula.