Target Heart Rate Calculator
Calculate training heart rate zones
Target Heart Rate Calculator tool
Target Heart Rate Calculator
Target Intensity Zones (Karvonen)
Target Heart Rate Calculator: key facts
- What it does
- Calculate training heart rate zones
- Category
- Health & Fitness Calculators
- Cost
- Free, with no account, sign-up, or install.
- Your data
- Runs entirely in your browser — the files and text you enter are never uploaded to a server.
- Last reviewed
- . Report an incorrect result.
What the Target Heart Rate Calculator does
Training by heart rate keeps your effort honest — too easy and you stall, too hard and you burn out. This calculator finds your personal training zones using the Karvonen method, which factors in your resting heart rate rather than relying on age alone, for ranges tailored to your fitness.
Runners, cyclists, and gym-goers use it to train deliberately: staying in the fat-burning zone for steady cardio, or pushing into the aerobic zone to build endurance. By starting from your heart rate reserve — the gap between your maximum and resting rates — it gives more individualized targets than a simple percentage of max heart rate.
Using the Target Heart Rate Calculator, step by step
- Enter your age (used to estimate your maximum heart rate).
- Enter your resting heart rate in beats per minute.
- Read your estimated maximum heart rate.
- Use the fat-burning and aerobic zone ranges to guide your workout intensity.
The Karvonen method, and why resting rate matters
Training zones can be set as straight percentages of maximum heart rate, but this tool uses the Karvonen method instead, which works from heart rate reserve — the span between your resting and maximum rates. Percentages are applied to that reserve and the resting rate is added back, which produces zones tailored to your own conditioning rather than to your age alone.
The difference is not cosmetic. Two people of the same age with resting rates of 45 and 75 have very different reserves, and percentage-of-maximum would hand them identical zones while Karvonen does not. A falling resting heart rate over months of training is itself one of the clearer signs that cardiovascular fitness is improving.
Maximum heart rate is estimated as 220 minus age. That formula is convenient, universally known, and quite imprecise — see below.
- At the default 25 years and a 60 bpm resting rate: maximum 195, reserve 135.
- That gives roughly 128–141 bpm for the easy zone at 50–60%, 141–155 for the aerobic zone at 60–70%, and 155–168 for the tempo zone at 70–80%.
- Improve conditioning until the resting rate falls to 50 and the reserve widens to 145, shifting the aerobic zone to about 137–152.
What makes this one worth using
- It uses the Karvonen heart-rate-reserve method, which incorporates your resting heart rate for more personalized zones than an age-only formula.
- It reports concrete beats-per-minute ranges for the fat-burning and aerobic zones, so you know exactly what to aim for on a monitor.
- It estimates your maximum heart rate for you from your age, so you do not need to test it.
- Calculations are instant and run entirely in your browser.
How rough the maximum estimate is
The 220-minus-age rule carries a standard deviation of roughly 10 to 12 beats per minute, which means a substantial share of people have a true maximum more than 20 beats away from their predicted one. Every zone derived from it inherits that error. Newer equations such as Tanaka's fit population data somewhat better, but no age-based formula can resolve individual variation — a supervised exercise test is the only way to establish a real maximum.
Measure your resting rate properly to get the most out of the method: take it on waking, before getting up or drinking coffee, ideally averaged over several mornings. A figure taken after activity or caffeine will be high and will skew every zone upward.
Other things move heart rate independently of effort: heat, dehydration, illness, poor sleep, stress, altitude, and stimulants all raise it, while beta blockers and some other medications lower it substantially and make age-predicted zones meaningless. Perceived exertion and the ability to hold a conversation are useful cross-checks. If you have a heart condition, high blood pressure, take cardiac medication, or are returning to exercise after a long gap or an illness, get zones set by a clinician or an exercise physiologist rather than a formula.
Frequently Asked Questions
What is the Karvonen method?
The Karvonen method calculates target heart rate using your heart rate reserve — the difference between your maximum and resting heart rates — rather than a flat percentage of maximum. Because it includes your resting rate, it produces zones tailored to your individual fitness level.
How is maximum heart rate estimated?
This calculator uses the common estimate of 220 minus your age. It is a population average, so your true maximum may differ by several beats; for precision, a supervised stress test is the gold standard, but the estimate works well for everyday training.
What is the difference between the fat-burning and aerobic zones?
The fat-burning zone (a lower-intensity range) emphasizes steady effort where a higher share of energy comes from fat. The aerobic zone is more intense, building cardiovascular endurance. Both are useful; the right one depends on your workout goal.
Do I need a heart rate monitor to use these zones?
To train by them accurately, yes — a chest strap or wrist monitor lets you keep your heart rate within the target range during exercise. Without one, you can approximate effort using perceived exertion, but a monitor is far more precise.
