Heart Rate Zone Calculator: Tanaka & Karvonen
Build your five training zones from a research-backed maximum heart rate, personalised further if you know your resting HR.
- 2 cited sources
- Calculates in your browser
Your answer
Appears here as you enter your details. No demo figures — the number is yours, or it is nothing.
Baseline
Know all your numbers
BMI, resting rate, daily burn, eating target, macros, body fat, waist ratios, heart-rate zones and your fitness age: 15 in all. Answer once, see them together, and stop whenever you like.
Get my Baseline →Methodology
Two published equations underpin the zones. First, maximum heart rate is estimated from age using the Tanaka equation, derived from a meta-analysis and laboratory validation spanning more than 18,000 people (Tanaka, Monahan & Seals, 2001):
HRmax = 208 − 0.7 × age
The familiar 220 − age rule is shown only for comparison. It has no
traceable original derivation and increasingly underestimates HRmax with
age.
If you provide a resting heart rate, zones are anchored to your heart-rate reserve using the Karvonen method (Karvonen, Kentala & Mustala, 1957):
target HR = (HRmax − resting HR) × intensity + resting HR
Without a resting HR, zones fall back to straight percentages of HRmax. Either way, five zones span 50 to 100% in ten-point bands.
Interpreting your result
Think of the zones as intensity buckets, not tripwires. Zones 1 to 2 are where most endurance volume belongs, conversational effort that builds the aerobic base. Zone 3 is steady "comfortably hard" work, zone 4 brackets your threshold, and zone 5 is short maximal efforts. If you train by feel as well as numbers, the zones should roughly match perceived effort; where they don't, trust the combination rather than either alone.
The Karvonen version is worth the extra measurement: two people of the same age with resting rates of 45 and 75 bpm have meaningfully different reserves, and percentage-of-max zones ignore that entirely.
Limitations
- Any age formula estimates the average HRmax for your age, individual measured maxima commonly sit ten or more beats either side, and medication (notably beta-blockers) shifts everything.
- Heart rate lags effort changes and drifts upward with heat, dehydration and duration; zones are most reliable for steady efforts.
- Wrist-based optical monitors misread during hard intervals; a chest strap is more dependable at high intensity.
- Chest pain, unexplained breathlessness or dizziness during exercise is a matter for a doctor, not a calculator.
Sources
Pull the receipts, 2 cited sources
Frequently asked questions
- How do I calculate my maximum heart rate?
- This tool uses the Tanaka equation (208 − 0.7 × age), which was derived from over 18,000 subjects and outperforms the older 220 − age rule, especially past age 40. Both are estimates, and measured maxima vary by ten or more beats either side.
- What are the five heart-rate zones?
- Zones 1 to 5 span 50 to 100% of your maximum (or of heart-rate reserve if you enter a resting HR): very easy recovery, easy aerobic, steady aerobic, threshold, and maximal work. Most endurance training time belongs in zones 1 to 2.
- What is the Karvonen method?
- Karvonen anchors zones to your heart-rate reserve, the span between resting and maximum, rather than raw percentages of max. Adding your resting heart rate makes zones noticeably better matched to your actual fitness.
- How do I find my resting heart rate?
- Measure on waking, before coffee or getting up: count your pulse for 60 seconds, or read it from a watch or strap averaged over several mornings. Typical adult values run from the 50s to low 70s; endurance athletes often sit lower.
- Why does my watch show different zones?
- Devices mix different HRmax formulas, reserve methods and zone boundaries, so small disagreements are normal. Whichever scheme you use, consistency matters more than the exact cut-offs.
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