Training Zone Calculator
Build endurance training zones three ways: heart-rate zones from your age (or a known maximum), using either a straight percentage of maximum or the Karvonen heart-rate-reserve method; cycling power zones from your Functional Threshold Power (FTP); and running pace zones from a threshold pace. Each zone comes with an explanation of what it trains and how it should feel. Zones are a widely used way to structure training intensity, but they are a guide, not medical advice — and estimated maxima carry a wide individual spread.
How to use this tool
- Choose the zone type: heart rate, cycling power, or running pace.
- For heart rate, enter your age (or a measured max HR) and pick percent or Karvonen; add a resting HR for Karvonen.
- For cycling power, enter your FTP in watts.
- For running pace, enter your threshold pace as M:SS per km.
- Read each zone’s range and what it trains — and treat it as a guide, not medical advice.
The formula
Endurance training is organised into intensity zones anchored to a maximum or threshold. Heart-rate zones use a percentage of maximum (or heart-rate reserve); cycling zones use a fraction of threshold power; running zones scale a threshold pace.
HRmax ≈ 208 − 0.7 × age (Tanaka)
zone_bpm = HRmax × zone% or rest + (HRmax − rest) × zone% (Karvonen)
power_zone = FTP × zone_fraction- HRmax
- Estimated maximum heart rate
- HRR
- Heart-rate reserve = HRmax − resting
- FTP
- Functional threshold power (cycling)
Zone models are training tools, not medical guidance. Estimated maxima carry a wide individual spread; a measured max or threshold is more accurate than any formula.
Worked examples
HR zones
- Given
- Age 30, % of max
- Result
- Max ≈ 187 bpm
Tanaka gives 208 − 0.7×30 ≈ 187 bpm. Zone 2 (60–70%) is about 112–131 bpm.
Karvonen
- Given
- Age 30, resting 60
- Result
- Zone 2 ≈ 136–149 bpm
Reserve = 187 − 60 = 127. Zone 2 = 60 + 127×0.6 to 60 + 127×0.7 ≈ 136–149 bpm.
Power zones
- Given
- FTP 250 W
- Result
- Threshold ≈ 228–263 W
Zone 4 is 91–105% of FTP, so 228–263 W for a 250 W FTP.
Frequently asked questions
The percentage method takes zones as a straight fraction of your maximum heart rate. The Karvonen method uses heart-rate reserve — the gap between resting and maximum — so it factors in your fitness via resting HR. Karvonen usually gives slightly higher zone boundaries and is often considered more individualised, but it needs an accurate resting heart rate.
This tool offers two formulas: Tanaka (208 − 0.7 × age), which is more accurate across ages, and the older Fox (220 − age). Both are population estimates with a wide spread — your true max can be 10–20 bpm either side. If you have a measured max from a test, enter it to override the estimate.
Functional Threshold Power is the highest average power (in watts) you can sustain for about an hour on the bike. It is commonly estimated from a 20-minute test (take about 95% of your 20-minute average) or measured directly. Power zones are then set as fractions of FTP using the Coggan model.
Threshold pace is roughly the pace you could hold in a hard, sustained effort of around an hour — close to a recent 10 km or 10-mile race pace for many runners. Enter it as minutes:seconds per kilometre, and the tool scales it into easier and faster zones.
No. Zones are a training tool to structure intensity, not medical guidance. The estimates carry real individual variation, and heart-rate response is affected by heat, caffeine, fatigue, medication and more. If you have any health concerns or are new to intense exercise, check with a doctor first.
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