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Karvonen method — 5 training zones, VO₂max estimate, and max HR comparison.
Measure first thing in the morning. Average adult: 60–80 bpm.
Enter your age and resting HR, then click Calculate
Max HR: Fox formula: 220 − age (Fox & Haskell, 1971). Tanaka formula: 208 − (0.7 × age) (Tanaka et al., 2001) — generally more accurate for adults over 40.
Karvonen Method: THR = ((Max HR − Resting HR) × intensity%) + Resting HR. First published by Martti Karvonen, 1957. Accounts for fitness level via heart rate reserve (HRR).
VO₂max (Uth formula): VO₂max ≈ 15 × (Max HR / Resting HR). Uth N et al., 2004. Moderate accuracy (±10%) without laboratory testing.
References: American Heart Association (2021). Target Heart Rates Chart. Fox SM & Haskell WL (1971). Karvonen M et al. (1957). Ann Med Exp Biol Fenn 35(3). Tanaka H et al. (2001). J Am Coll Cardiol 37(1).
Karvonen formula calculates target HR using HR reserve (HRR = max HR − resting HR). THR = (HRR × intensity%) + resting HR. This accounts for your fitness level unlike simple % of max HR.
Zone 1 (50–60%): Recovery. Zone 2 (60–70%): Aerobic base/fat burn. Zone 3 (70–80%): Aerobic endurance. Zone 4 (80–90%): Lactate threshold. Zone 5 (90–100%): VO₂max. Train 80% of volume in Zone 2.
Uth formula: VO₂max ≈ 15 × (Max HR / Resting HR). For max HR 190, resting HR 60: VO₂max ≈ 47.5 ml/kg/min. Accurate measurement requires lab testing.
220 − age (Fox, 1971) is the most common. 208 − (0.7 × age) (Tanaka, 2001) is more accurate for adults. A graded exercise test gives the most precise value.
Calculate your five aerobic training zones with the Karvonen heart-rate-reserve method, compare two estimates of maximum heart rate, and get a target heart rate for any chosen intensity.
HRmax is the highest sustainable heart rate during exhaustive exercise. The classic Fox formula 220 − age has a standard error of ±10–12 bpm. Tanaka's 208 − 0.7 × age is statistically more accurate, especially for adults over 40.
Karvonen's method is preferred over %HRmax because it uses heart-rate reserve (HRmax − HRrest), which scales the zones to your individual fitness.
Five common zones are: Z1 50–60 %, Z2 60–70 %, Z3 70–80 %, Z4 80–90 %, Z5 90–100 % of HRR. Most aerobic adaptation happens in Z2; high-intensity intervals target Z4–Z5.
HRmax = 220 − age — Population estimate, ±10 bpm.HRmax = 208 − 0.7 × age — More accurate for older adults.HRR = HRmax − HRrest — Working range above resting.THR = HRR × intensity% + HRrest — Per-zone heart rate.Inputs: Age 30, resting HR 60.
HRmax ≈ 190HRR = 190 − 60 = 130Z2 (60–70 %) = 138–151 bpmZ4 (80–90 %) = 164–177 bpmResult: Z2 138–151, Z4 164–177 bpm.
Target HR = (HRmax − HRrest) × intensity% + HRrest, using heart-rate reserve.
Tanaka has lower bias for adults over 40; Fox is fine for younger adults.
Lying down, first thing in the morning before getting up — average over 3 days.
Maximum fat percentage occurs around Z2 (60–70 % HRR), but absolute kcal from fat is similar across moderate intensities.
HR zones are similar, but cycling HRmax is often 5–8 bpm lower than running HRmax.
Cardiac drift from heat, dehydration, and fatigue can raise HR 5–10 bpm at the same effort.
They suppress HR — use perceived exertion instead and consult your clinician.
Optical wrist sensors are usually within ±5 bpm in steady state; intervals can be unreliable.
No — most plans use 80 % Z1–Z2 and 20 % Z4–Z5 (polarised model).
HRR uses your resting HR as a baseline; %HRmax does not. HRR adapts better to fitness changes.
Many guidelines recommend perceived exertion over fixed HR zones during pregnancy.
No — educational only.
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