Target Heart Rate Calculator
Find your training heart-rate zones using the Karvonen formula.
Inputs
Allowed range: 10 to 100
Allowed range: 30 to 120
Results
Estimated max heart rate
190 bpm
Heart-rate reserve
125 bpm
Zone 1 — Warm-up (50–60%)
128–140 bpm
Zone 2 — Easy / fat-burn (60–70%)
140–153 bpm
Zone 3 — Aerobic (70–80%)
153–165 bpm
Zone 4 — Threshold (80–90%)
165–178 bpm
Zone 5 — Maximum (90–100%)
178–190 bpm
How it works
We estimate maximum heart rate as HRmax = 220 − age, then apply the Karvonen reserve method: THR = (HRmax − HRrest) × intensity + HRrest. Zones use 50–60% (warm-up), 60–70% (fat-burn / easy), 70–80% (aerobic), 80–90% (threshold), 90–100% (max).
Complete guide
Enter your age and resting heart rate (measure first thing in the morning, lying down, for the best reading).
We return your estimated max HR and the bpm range for each training zone.
Use Zone 2 (60–70%) for long, easy aerobic work, Zone 3–4 for tempo intervals, and short bouts in Zone 5 for VO₂max sessions.
Frequently asked questions
- How accurate is 220 − age?
- It is a rough estimate with ±10–12 bpm individual variation. A field test (e.g., a hard 5K) gives a more personal max.
- Why use the Karvonen formula?
- It accounts for your resting HR, so zones better reflect actual cardiovascular load than a pure %-of-max calculation.
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