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About this tool
Training zones from the Karvonen heart rate reserve method using your resting and maximum heart rate.
The Karvonen method sets training zones from heart rate reserve — target heart rate = ((maximum HR − resting HR) × intensity) + resting HR — rather than from a flat percentage of maximum heart rate. Because it anchors the bottom of the scale at your own resting pulse, two people the same age get different zones if one is fitter. Enter your resting heart rate plus either your age or a measured maximum, and you get all five zones in beats per minute along with any custom intensity you want to check.
Open Karvonen Heart Rate Calculator on AltFTool — it loads instantly in your browser.
Enter the values you already know.
Fine-tune the options to match your scenario.
Read the result and use it in your planning or reporting.
Heart rate reserve moves as your resting pulse falls, so zones track your conditioning rather than only your birthday.
Switch between Tanaka, Fox, Gulati and Nes, or override them entirely with a lab-measured maximum.
Each band shows both the bpm range and what the session is actually training, from recovery to VO2 max.
Target heart rate = ((maximum heart rate − resting heart rate) × intensity percentage) + resting heart rate. The bracketed term is heart rate reserve. For a max of 187 bpm and a resting rate of 60 bpm, the reserve is 127 bpm, so 70% intensity gives (127 × 0.70) + 60 ≈ 149 bpm.
It usually tracks oxygen uptake more closely, because %HRR corresponds roughly one-to-one with %VO2 reserve while a plain %HRmax does not. The practical difference is largest at low intensities: 60% of max HR is a much easier effort than 60% of heart rate reserve, often 15-20 bpm apart.
Take it immediately on waking, lying still, before caffeine or standing up, and average three to five mornings. A single reading can be off by 5-10 bpm because of sleep quality, alcohol or a full bladder, and the average is what your zones should be built on.
Only as a rough starting point — the Fox 220 − age equation has a standard deviation of about 10-12 bpm and systematically underestimates maximum heart rate in older adults. Tanaka's 208 − 0.7 × age fits population data better, but a supervised maximal test or a hard field test gives a far more reliable number. This tool is informational; check with a doctor before doing maximal-effort testing.
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