Heart-rate zone calculator: four methods, transparent numbers
Enter your maximum heart rate, resting heart rate or lactate-threshold heart rate (LTHR) to calculate zones using Karvonen, Friel and Coggan. If you do not know your maximum, we can estimate it from age. Save the result in SkolCoach or share it by link.
This method requires: Max HR and resting heart rate. Complete the fields above and your zones will appear automatically.
Which method should you choose?
- Karvonen (heart-rate reserve) is the best starting point when you know Max HR and resting heart rate. It accounts for fitness: a trained athlete’s lower resting heart rate shifts the zones accordingly.
- Friel from Max HR provides seven zones from maximum heart rate. It is simple and widely used but does not account for resting heart rate.
- Friel or Coggan from LTHR are the most accurate practical options because they are anchored to lactate-threshold heart rate, a direct marker of current fitness. You need an LTHR test result.
How to measure the inputs
- Resting heart rate — measure before getting out of bed on three consecutive mornings and use the average, or check your overnight minimum on your watch.
- Max HR — after warming up, perform 2–3 three-minute uphill efforts with an all-out finishing acceleration. The highest reading should be close to your true maximum. The 220-minus-age formula can miss by 10–15 bpm and is only an estimate.
- LTHR — during a 30-minute test, hold the highest even effort you can sustain at race intensity. Average heart rate over the final 20 minutes estimates LTHR. A laboratory lactate test is more precise.
How to use your zones
The key principle is polarisation: spend roughly 80% of training time in the first two zones at easy intensity, with the remainder in short quality sessions at threshold and above. The middle zone is a common trap: hard enough to create fatigue, but not targeted enough to drive efficient adaptation.
Learn more in our guides: why easy volume makes you faster, lactate and thresholds explained and the Norwegian method, where these zones become practical training tools.
To prevent training volume from increasing too quickly, check your progression in the ACWR calculator.
FAQ
How accurate is age-based Max HR estimation?
Tanaka’s formula, 208 − 0.7 × age, is a useful population estimate, but an individual result can easily differ by ±10–12 bpm, shifting zones by roughly half a zone. It is suitable for getting started; after a month or two, perform a field test and recalculate.
Are running and cycling heart-rate zones the same?
No. Cycling LTHR is typically 5–8 bpm lower than running LTHR because less muscle mass is involved and there is no impact loading; swimming values are usually lower still. Triathletes should calculate discipline-specific zones from the corresponding LTHR.
My watch calculates zones automatically. Why use a calculator?
Watches often derive zones from an estimated Max HR and inherit its error. A calculator based on measured Max HR, resting heart rate or LTHR is more precise. You can then enter those zones manually into Garmin or COROS.
Do heart-rate zones change over time?
Yes. After two or three months of consistent training, threshold heart rate and pace at a given heart rate can improve, warranting recalculation. SkolCoach tracks these trends and proposes threshold updates when your training data supports them.
See how it works with your own data
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