Target Heart Rate Calculator a zone, in beats
Enter your age and, if you know it, your resting pulse. You get the beats per minute your chosen training zone actually means for your body.
Resting Pulse Changes Everything
With it the calculator uses Karvonen; without it, a plain percentage that reads much lower.
A Predicted Maximum
Individual maximum heart rates vary by roughly ±10 bpm around any equation.
What is a target heart rate?
At a Glance
A target heart rate is the band of beats per minute that corresponds to a training intensity. Programmes are written in zones — "zone 2 for 45 minutes" — but a strap shows beats, and turning one into the other needs your maximum heart rate and, ideally, your resting one.
Two steps, and the second one is where most calculators quietly lose accuracy.
Step one: predict the maximum. The familiar "220 minus age" comes from Fox in 1971 and was never meant as a precise equation. Tanaka's 2001 meta-analysis of 351 studies produced a better fit across the adult age range:
HRmax = 208 − 0.7 × ageThe two equations cross at age 40 and separate from there: at 25, Fox says 195 and Tanaka 190.5; at 60, Fox says 160 and Tanaka 166. According to Tanaka and colleagues, the older rule systematically over-predicts in young adults and under-predicts in older ones.
Step two: convert intensity into beats. A plain percentage of maximum ignores where your heart actually starts from. The Karvonen method works from heart-rate reserve — the room between resting and maximum — and adds the resting rate back:
target = ((HRmax − HRrest) × intensity) + HRrestThe difference is large. At 70 % intensity, Karvonen gives 144 bpm and a plain percentage gives 126 — 18 beats apart, which is the difference between a genuine aerobic effort and a walk.
These are the values the calculator loads by default.
Predict the maximum
208 − 0.7 × 40 = 180 bpm.
Find the heart-rate reserve
180 − 60 = 120 bpm of room between resting and maximum.
Apply the zone
Zone 3 is 70-80 % of the reserve: 120 × 0.70 = 84 and 120 × 0.80 = 96.
Add the resting rate back
84 + 60 = 144 bpm and 96 + 60 = 156 bpm. That is the moderate band.
Compare without the resting rate
Plain percentages give 126 to 144 for the same zone — a whole band lower. If you have a resting pulse, use it.
The band is a guide rail, not a rule. Perceived effort and how you feel the next day are still better signals than any number.
Zone 2 is where most endurance training belongs. For a 40-year-old with a resting pulse of 60, that is 132 to 144 bpm — conversational, sustainable, and boring enough that most people go too hard instead.
Zone 5 is a short-interval tool. 168 to 180 bpm in the same example. It is meant for minutes, not for a whole session.
Your true maximum may not be 180. Prediction equations carry a standard deviation of roughly 10 bpm, so an individual can be 170 or 190 with nothing wrong. If your easy runs consistently sit above the predicted zone 2, the prediction is probably low rather than your effort high.
Resting heart rate is a training signal in itself. It typically falls as fitness improves, and a resting pulse several beats above your normal often signals fatigue or illness. Re-measure it every few weeks and re-run this calculation.
Medication matters more than the equation. Beta blockers and some other drugs cap heart rate outright, which makes every zone here meaningless. Use perceived effort and talk to your doctor.
To see what a session costs in energy, use the Calories Burned Calculator; for running pace, the Pace Calculator.
What a predicted maximum cannot know
This calculator is for informational purposes and is not medical advice or a diagnosis.
- Predicted maxima vary by about ±10 bpm between individuals of the same age. Only a supervised maximal test measures yours.
- The equations are population fits. Tanaka is the best of the three across adults, but none is exact for a specific person.
- Medication can invalidate the whole model. Beta blockers, some antiarrhythmics and other drugs suppress heart rate independently of effort.
- Heat, altitude, dehydration, caffeine and stress all shift heart rate at a given workload, sometimes by ten beats or more.
- Wrist optical sensors lag and miscount during intervals and weights; a chest strap is far more reliable for zone work.
- Not validated for children or during pregnancy, where different guidance applies.
If you have a heart condition, take heart-rate-affecting medication, or are returning to exercise after a long break, discuss target intensities with a doctor before training to them.