What is the Karvonen method for heart rate zones?

The Karvonen method (Heart Rate Reserve method) calculates training zones relative to your Heart Rate Reserve (HRR = HRmax − resting HR). Zone target = resting HR + (% × HRR). This is more personalized than using % of HRmax alone because it accounts for your individual fitness level reflected in resting heart rate.

How do I find my maximum heart rate?

Two common formulas: Fox formula: HRmax = 220 − age (most widely used, simple); Tanaka formula: HRmax = 208 − (0.7 × age) (considered more accurate for older adults, from a 2001 study by Tanaka et al.). A true HRmax can only be determined by a graded exercise test to exhaustion under medical supervision.

What is Zone 2 training and why is it popular?

Zone 2 (Fat Burn, 60–70% of HRmax or HRR) is aerobic base training at a conversational pace. It maximizes mitochondrial density, fat oxidation and cardiovascular efficiency with low injury risk. Many endurance coaches recommend spending 70–80% of total training volume in Zone 2.

How many calories do I burn in each heart rate zone?

Calorie burn increases with intensity: Zone 1 roughly 200–350 kcal/h, Zone 2 350–500 kcal/h, Zone 3 500–650 kcal/h, Zone 4 650–800 kcal/h, Zone 5 800–1000+ kcal/h. Actual values depend on body weight, fitness level and individual metabolism. This calculator shows approximate estimates based on typical values.

● Cardio & running

Your Heart Rate Training Zones — personalized.

Enter your age and resting heart rate to get 5 training zones in bpm, calculated with the Karvonen method or % of HRmax (Fox & Tanaka). Visual bar chart included.

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Heart Rate Zones — Training Zones

Karvonen or % of HRmax — 5 zones with bpm ranges and calorie estimates

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Your data

Age — years

yrs

Resting heart rate — measured at rest, ideally after waking

bpm

Method

HRmax formula

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Your zones

HRmax (Fox) 220 − age—

HRmax (Tanaka) 208 − 0.7 × age—

Using HRmax selected formula—

HRR HRmax − resting HR—

Zone	bpm range	kcal/h

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How it's calculated

Two methods, five zones — and the math behind them

Heart rate training zones divide your exercise intensity into 5 bands based on maximum heart rate (HRmax). The Karvonen method personalizes these zones using your Heart Rate Reserve (HRR = HRmax − resting HR), giving more accurate targets than a simple percentage of HRmax. For a 30-year-old with a resting HR of 60 bpm, Karvonen Zone 2 (fat burn) spans roughly 130–146 bpm.

There are two common approaches. The % of HRmax method simply multiplies your maximum heart rate by zone percentages. The Karvonen method (Heart Rate Reserve) accounts for your resting heart rate, which reflects your cardiovascular fitness — making it more individualized and widely recommended for trained athletes.

HRmax (Fox) = 220 − age
HRmax (Tanaka) = 208 − (0.7 × age)
HRR = HRmax − Resting HR
Zone target (Karvonen) = Resting HR + (% × HRR)
Zone target (% HRmax) = % × HRmax

1
Calculate HRmax with both formulas
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2
Calculate Heart Rate Reserve (HRR)
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3
Apply zone percentages to get bpm ranges
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4
Zone 2 (fat burn) lower–upper bounds
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Understand the terms

HRmax (Maximum Heart Rate): The highest number of beats per minute your heart can achieve during maximum exertion. Age-predicted formulas give an estimate; only a graded exercise test gives the true value.
HRR (Heart Rate Reserve): HRmax minus resting heart rate. Used in the Karvonen formula to make zone calculations more individualized. A lower resting HR produces a larger HRR and wider zones.
Karvonen formula: Zone target HR = Resting HR + (intensity % × HRR). Developed by Finnish physician Martti Karvonen in 1957, it produces more personalized targets than simple % of HRmax.
Aerobic threshold: The exercise intensity (approximately Zone 2/3 boundary, ~70–75% HRmax) at which the body transitions from predominantly aerobic to mixed fuel use. Training below this threshold builds aerobic base.
Anaerobic threshold (Lactate threshold): The intensity (approximately Zone 4, ~85–90% HRmax) at which lactate production exceeds clearance, causing rapid fatigue. Raising this threshold is a key goal of endurance training.

See the full glossary →

Disclaimer: estimation tool for informational and training-planning purposes, using the Fox (1971) and Tanaka (2001) HRmax formulas and the Karvonen (1957) method. Age-predicted HRmax can differ from true HRmax by ±10–12 bpm. Calorie estimates are approximate and vary significantly by body weight and fitness. Does not replace assessment by a certified exercise physiologist or sports medicine physician.

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Frequently asked questions — Heart Rate Zones

What are heart rate training zones?

Heart rate training zones are bpm ranges corresponding to different exercise intensities. The standard 5-zone model divides effort from very light recovery (Zone 1) to all-out maximum effort (Zone 5), each zone stimulating different physiological adaptations — fat oxidation, aerobic capacity, lactate threshold, and VO2max.

What is the Karvonen method and why is it better?

The Karvonen (Heart Rate Reserve) method calculates zones using: target HR = resting HR + (% × HRR), where HRR = HRmax − resting HR. It's more personalized than simple % of HRmax because it accounts for your resting heart rate, which reflects your cardiovascular fitness. A trained athlete with a low resting HR gets different — more accurate — zones than a sedentary person at the same age.

What is Zone 2 training and why is it so popular?

Zone 2 (Fat Burn, 60–70%) is a conversational-pace aerobic effort that maximizes mitochondrial density and fat oxidation while producing minimal fatigue. Many endurance coaches recommend spending 70–80% of total training volume in Zone 2. It builds the aerobic base that makes all other training zones more effective.

How accurate is age-predicted maximum heart rate?

Age-predicted HRmax formulas (Fox: 220−age; Tanaka: 208−0.7×age) are population averages with a standard deviation of ±10–12 bpm. Your true HRmax may be significantly higher or lower. Tanaka's formula (2001) is generally considered more accurate for adults over 40. For precise zones, a graded exercise test under medical supervision is recommended.

What is the difference between the Fox and Tanaka HRmax formulas?

Fox formula (220 − age) has been the standard since 1971 and is simple but overestimates HRmax in older adults. Tanaka formula (208 − 0.7 × age) from a 2001 meta-analysis of 351 studies is considered more accurate, especially for people over 40, as it accounts for the non-linear decline in HRmax with age. For younger adults both give similar results.

📚 Learn more — official sources

🔬 Study Tanaka et al. (2001) — Age-predicted maximal heart rate revisited Meta-analysis of 351 studies (18,712 subjects) establishing the Tanaka formula HRmax = 208 − 0.7 × age, published in JACC. See on PubMed → 🏛️ Organization ACSM — Guidelines for Exercise Testing and Prescription American College of Sports Medicine official guidelines covering heart rate zones, training intensity, and exercise prescription for health and performance. See official source → 🔬 Study Karvonen et al. (1957) — The effects of training on heart rate Original landmark study by Martti Karvonen proposing the Heart Rate Reserve method for calculating training intensity targets. See on PubMed → 🏛️ Organization WHO — Physical activity guidelines for adults World Health Organization global recommendations on physical activity and sedentary behaviour, including intensity guidelines for cardiovascular health. See official source →

Heart Rate Zones Calculator

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About the Heart Rate Zones Calculator

Heart rate training zones are the cornerstone of structured endurance training. This calculator uses two scientifically validated HRmax formulas — Fox (220 − age) and Tanaka (208 − 0.7 × age) — combined with either the Karvonen Heart Rate Reserve method or simple percentage of HRmax, to produce personalized training zones. The Karvonen method, published in 1957, remains the gold standard for individualized zone calculation because it incorporates resting heart rate as a marker of cardiovascular fitness.

The 5-zone model divides training intensity from light recovery (Zone 1) through fat-burning aerobic base (Zone 2), tempo aerobic (Zone 3), lactate threshold (Zone 4) and all-out VO2max efforts (Zone 5). Training in the right zone at the right time is fundamental to periodization programs used by recreational and elite athletes alike. Calorie estimates shown are approximate and based on typical energy expenditure values from ACSM guidelines.