Heart Rate Zone Calculator
Estimate running heart rate zones from age, known max heart rate, or heart rate reserve, then compare Zone 1 through Zone 5 by feel and training use.
Last updated: June 15, 2026
How this calculator works
Estimated max heart rate = 208 - 0.7 x age. Percent-max zones use 50-100% of max HR; heart-rate-reserve zones add resting HR to the reserve percentage.
Using a heart rate zone calculator for quick training guidance, Zone 2 running ranges, and optional heart-rate-reserve context.
Age-estimated max heart rate can be far off for individuals. Lab-tested max HR, threshold testing, or resting-heart-rate methods can produce more personal zones.
A 40-year-old has an estimated max HR of 180 bpm, with Zone 2 at about 108-126 bpm.
Sources and assumptions
- Running Toolkit methodology and sources
Documents the formula choice, unit handling, assumptions, and limits behind this calculator.
- Max heart rate formula context
Supports context for Tanaka-style age-estimated maximum heart rate when a runner does not enter a known max HR.
How to use it
- Enter age for a quick estimated max heart rate.
- Enter a known max heart rate if you have one from reliable testing.
- Use heart-rate reserve when you also know resting heart rate.
- Use the zones and feel labels as broad training ranges rather than exact physiological thresholds.
Common mistakes
- Assuming age-estimated max heart rate is exact.
- Treating percentage-of-max zones as the same as lactate-threshold zones.
- Ignoring cardiac drift, heat, caffeine, fatigue, and sensor quality.
Useful for
- Estimate an easy run or Zone 2 heart-rate range.
- Compare heart-rate intensity with pace from the pace calculator.
- Use known max HR to make zones more personal than age-only estimates.
- Compare percent-of-max and heart-rate-reserve ranges for easy and aerobic training.