Heart Rate Zones Calculator
Enter your age (and optional resting heart rate) to see max HR and five standard training zones — from recovery to VO₂ max effort.
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Result
The formula
Estimated max HR uses the common 220 − age formula (Fox et al.). Five zones use % max HR: Z1 50–60%, Z2 60–70%, Z3 70–80%, Z4 80–90%, Z5 90–100%. With resting HR, the Karvonen method sets target = (max − rest) × intensity + rest.
Worked example
- Age 30 → max HR ≈ 190 bpm
- Zone 2 (60–70%): 114–133 bpm
- With rest HR 60: Karvonen Z2 ≈ 138–151 bpm
Result: Zone table for age 30
Using heart rate zones
Zones structure aerobic training — easy days easy, hard days hard.
220 − age
Simple but individual max HR varies ±10–12 bpm. Lab or field tests refine it; 220 − age is a starting estimate cited in ACSM materials.
Five-zone model
Zone 1 recovery, Zone 2 aerobic base, Zone 3 tempo, Zone 4 threshold, Zone 5 VO₂ max. Most endurance training accumulates in Z1–Z2 with selective Z3–Z5 work.
Karvonen advantage
Heart rate reserve (max − resting) personalizes targets for fit people with low resting HR — otherwise % max HR is simpler.
Interesting facts
Not exact for everyone
Max HR does not drop precisely 1 bpm per birthday. Medications (beta blockers) blunt HR response — zones may not apply.
Polarized training
Many endurance programs emphasize lots of easy Z1–Z2 plus small doses of Z4–Z5, with less moderate “gray zone” time.
220 − age origin
Popularized from Fox et al. (1971) regression — convenient though individual variance is large.
Resting HR context
Lower resting HR often reflects aerobic fitness. Karvonen uses that reserve to set targets.
Pairs with pace
Runners often cross-check HR zones with pace from a running pace calculator for race planning.
Frequently asked questions
This calculator estimates 220 − your age in years. A 35-year-old gets ~185 bpm — individual tests may differ.
Zone 2 is often labeled “fat burning” because fat supplies more energy at moderate intensity — total calorie burn still rises at higher zones.
Target HR = (max HR − resting HR) × intensity% + resting HR. It uses heart rate reserve instead of simple % max.
No. Cardiac patients and people on HR-limiting medications should follow clinician or cardiologist guidance.
Zone 2 (about 60–70% of max HR) burns the highest percentage of calories from fat, but total calories and total fat burned both rise at higher intensities over the same duration.
It is a population average with roughly ±10–12 bpm individual variance. A supervised max-effort test or a recent race result gives a more personal number than the formula alone.
Most endurance athletes spend 70–80% of training volume in Zone 1–2 (easy, conversational pace) and use Zone 4–5 sparingly for intervals, following a polarized or pyramidal training model.
Yes. Aerobic training typically lowers resting heart rate over weeks to months as the heart becomes more efficient — re-enter your updated resting HR for more accurate Karvonen zones.
References
- Physical activity and cardiovascular health (ACSM) Exercise intensity and HR context.
- Age-predicted maximal heart rate (Fox et al.) 220 − age regression source.