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.
- Recovery
- 2 cited sources
- Runs in your browser
Your estimated maximum heart rate
187 bpm
Tanaka equation (208 − 0.7 × age). The legacy 220 − age rule gives 190 bpm. Zones below use %HRmax — add your resting HR for more personal zones.
| Zone | Effort | Heart rate (bpm) |
|---|---|---|
| Z1 | Very easy — recovery | 94–112 |
| Z2 | Easy — aerobic base | 112–131 |
| Z3 | Steady — tempo | 131–150 |
| Z4 | Hard — threshold | 150–168 |
| Z5 | Maximal — VO₂ work | 168–187 |
Formula-based maxima are estimates — measured values commonly differ by ten or more beats either way. Anchor training to how zones feel as much as to the numbers.
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 50–100% in ten-point bands.
Interpreting your result
Think of the zones as intensity buckets, not tripwires. Zones 1–2 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 — measured maxima vary by ten or more beats either side.
- What are the five heart-rate zones?
- Zones 1–5 span 50–100% 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 1–2.
- 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.
Written and reviewed by Mathew Beale — MSc Biotechnology, University of Reading.
Last reviewed:
Related tools
- Sleep Calculator — When To Go To Bed
Free sleep cycle calculator: enter your wake-up time and get bedtime options for 4, 5 or 6 full 90-minute cycles, including 15 minutes to fall asleep.
- Running Pace Calculator — Pace, Speed & Splits
Free running pace calculator: min/km and min/mile pace, speed, and kilometre splits for any distance from 400 m to ultra distances.
- TDEE Calculator — Total Daily Energy Expenditure
Estimate your total daily energy expenditure (TDEE) and BMR with the Mifflin–St Jeor, Katch–McArdle or revised Harris–Benedict equations. Free, no sign-up.