Target Heart Rate Calculator
Find your five training zones in beats per minute, by %HRmax or the Karvonen method.
Your details
Every maximum-heart-rate formula is a population average with a spread of about 10–12 bpm either way, so a perfectly normal 40-year-old can top out anywhere from 160 to 195. If you have heart disease, take beta blockers, or are new to hard exercise, get zones set from a supervised test rather than an equation.
This works out training heart rate zones from your maximum and resting heart rates.
It uses the Karvonen heart-rate-reserve method, which gives more personal zones than a flat percentage of maximum.
How training heart rate zones work
Target heart rate zones translate a training intensity into a number you can watch. The problem is that two common methods give very different answers, and most tools do not say which they used.
The percentage of maximum method is simply max × intensity. With a maximum of 190, 70% is 133 bpm. The Karvonen method works from your heart rate reserve, the gap between resting and maximum, and adds your resting rate back. With a resting rate of 60, 70% becomes 151 bpm.
Eighteen beats is not a rounding difference. It is the gap between a conversational run and a genuinely hard one. Karvonen is the better method, because it accounts for your own resting heart rate rather than assuming everyone starts from zero.
The flat method treats zero as the bottom of the range. Karvonen treats your resting rate as the bottom, which is what your body actually does.
What to enter
- Maximum heart rate
- Measured if you have it, otherwise estimated. The Tanaka equation beats 220 − age.
- Resting heart rate
- Measured on waking, before getting up, averaged across several mornings. This is what makes Karvonen personal.
- Target intensity
- As a percentage. 60-70% for easy aerobic work, 80-90% for threshold effort.
The five zones, and what each is for
- Zone 1: 50-60%
- Recovery and warm-up. Very easy, and genuinely useful between hard sessions.
- Zone 2: 60-70%
- Easy aerobic. Builds the aerobic base, and most endurance training should live here.
- Zone 3: 70-80%
- Aerobic endurance. Comfortably hard, and where too much training tends to accumulate.
- Zone 4: 80-90%
- Threshold. Hard, sustainable for limited periods, and the zone that improves lactate threshold.
- Zone 5: 90-100%
- Maximal intervals. Short efforts with full recovery.
What this assumes
Zones are only as good as the maximum heart rate they are built on. An estimated max carries an error of roughly 10-12 bpm, and every zone inherits it.
Heart rate lags effort by a minute or two and drifts upward over long sessions in heat. It describes short intervals poorly.
How to calculate your target heart rate zones
Use heart rate reserve rather than a flat percentage.
- HRmax − HRrest
- Heart rate reserve, the range you actually train within
- intensity
- As a decimal, so 70% is 0.70
- + HRrest
- Added back, because your heart never goes below resting
Measure your resting heart rate. On waking, before getting up, across several mornings. A fitness tracker's overnight low works well.
Get a maximum heart rate figure. Measured is best. Otherwise the Tanaka equation: 208 − 0.7 × age.
Work out heart rate reserve. Maximum minus resting. With 190 and 60 that is 130 bpm of range.
Apply the intensity and add resting back. 70%: (130 × 0.7) + 60 = 151 bpm. Cross-check it against how the effort actually feels.
See a worked example: the full set of zones
- Maximum
- 190 bpm
- Resting
- 60 bpm, so a reserve of 130
Zone 1 at 50%: (130 × 0.5) + 60 = 125 bpm.
Zone 2 at 60%: 138 bpm. Zone 3 at 70%: 151 bpm.
Zone 4 at 85%: 171 bpm.
By the flat-percentage method the same intensities give 95, 114, 133 and 162, which would have you training considerably easier than intended throughout.
151 bpm at 70% by Karvonen
Frequently asked questions
It sets zones as a percentage of heart rate reserve, the gap between your resting and maximum rates, then adds your resting rate back.
It is more personal than a flat percentage of maximum, because two people with the same maximum but different resting rates genuinely have different training ranges.
Because they use different methods and different maximum heart rate equations, and most do not say which.
The method matters most: 70% of a 190 max is 133 by the flat method and 151 by Karvonen. Check which one a tool is using before trusting its numbers.
Most endurance training should be zone 2, easy enough to hold a conversation. Many people run everything in zone 3, which is too hard to recover from and too easy to drive adaptation.
A common pattern is roughly 80% easy and 20% hard. The hard sessions matter, and they only work if the easy ones are genuinely easy.
On waking, before getting up, for a full minute. Average several mornings, since it varies day to day with sleep, stress, alcohol and illness.
A fitness tracker's overnight low is a good proxy. As a rough guide, 60-100 bpm is the normal adult range and trained endurance athletes are often in the 40s.
Considerably, especially at high intensity. Wrist optical sensors can lag during rapid changes and sometimes lock onto arm cadence instead of pulse.
For steady-state training a watch is fine. For intervals or threshold work, a chest strap is worth having.
Cardiac drift: at the same pace and effort, heart rate rises over a long session as body temperature climbs and blood volume falls through sweating.
It is normal and expected. On long efforts, pace or perceived effort is a better guide than a fixed heart rate ceiling.
Problems people actually run into
Not knowing which method your tool used
The same 70% target is 133 bpm or 151 bpm depending on the method, and most calculators do not label which they applied.
Eighteen beats changes an easy run into a hard one. Check the method, and prefer Karvonen since it uses your own resting rate.
Training everything in the middle
Zone 3 feels productive: fast enough to seem like training, slow enough to sustain. It builds less aerobic base than easy running and less speed than hard intervals.
Push the easy days genuinely easy and the hard days genuinely hard. The middle is where a lot of training effort quietly goes to waste.
Results are estimates for general information only and are not professional financial, medical, or legal advice. Read our full disclaimer.
Last updated: September 4, 2026