Heart Rate Zones Calculator
Free max heart rate and training zones calculator. Enter your age (optionally with resting HR for Karvonen) and get the 5 cardio zones in bpm.
Type your age and optionally your resting heart rate. The calculator estimates your max HR and the five training zones in bpm.
Max heart rate
HRmax ≈ 220 − age
This is the textbook Fox formula — a quick estimate of the average max HR for a given age, accurate to roughly ±10 bpm for any individual.
Zone formulas
If you supply a resting HR, the Karvonen (heart-rate-reserve) method is used:
target = (HRmax − HRrest) × intensity + HRrest
If not, plain percent-of-max:
target = HRmax × intensity
The zones live at 50–60%, 60–70%, 70–80%, 80–90%, 90–100% of intensity.
What each zone is for
| Zone | % intensity | Purpose |
|---|---|---|
| Z1 | 50–60% | Recovery / very easy |
| Z2 | 60–70% | Aerobic base — the bulk of long runs |
| Z3 | 70–80% | Tempo / aerobic threshold |
| Z4 | 80–90% | Lactate threshold / VO₂max intervals |
| Z5 | 90–100% | Maximal — sprints and short hard intervals |
Not medical advice
The 220 − age formula is a population estimate. Real max HR varies by individual. Get a checkup before starting hard training, especially if there are cardiovascular risk factors.
Worked examples
-
30-year-old, percent-of-max
Max HR 190 bpm · Z1 95–114 · Z2 114–133 · Z3 133–152 · Z4 152–171 · Z5 171–190
-
Same age with rest HR 60 (Karvonen)
Max HR 190 bpm · Z1 125–138 · Z2 138–151 · Z3 151–164 · Z4 164–177 · Z5 177–190
Frequently asked questions
How is the maximum heart rate estimated?
We use the textbook "220 − age" (Fox formula). It's a population average — individual maxima can vary by ±10–12 bpm. Newer formulas such as Tanaka's (208 − 0.7 × age) are slightly better for older adults but the differences in the resulting zones are small.
What's the difference between %max and Karvonen?
Percent-of-max takes a flat percentage of your max HR. The Karvonen method (heart-rate reserve) accounts for your resting HR: target = (max − rest) × intensity + rest. It gives slightly higher target ranges for people with low resting HR (i.e. fitter), and is generally considered more accurate when resting HR is known.
What are the five zones for?
Z1 (50–60%) recovery / very easy. Z2 (60–70%) aerobic / endurance base — the bulk of long runs. Z3 (70–80%) tempo / aerobic threshold. Z4 (80–90%) lactate threshold / VO₂max interval work. Z5 (90–100%) maximal — sprints and short hard intervals.
Why is this estimate, not measurement?
True max HR varies between individuals and is best determined by a maximal effort test (e.g. graded treadmill) under supervision. The 220 − age estimate is good enough for general training programming but should not be used to make medical decisions or to push very hard without other context.
This isn't medical advice, right?
Correct — it's general fitness math. Consult a qualified professional before starting an intense training program, especially if you have cardiovascular risk factors.
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