Heart Rate Zone Calculator
Get your five heart-rate training zones from age and resting heart rate using the Karvonen method — fat burn, cardio and peak zones in bpm.
How the zones are calculated
Your maximum heart rate is estimated from age — either the classic 220 − age or the
Tanaka formula (208 − 0.7 × age), which tracks real-world maxima better, particularly past 40.
Each training zone is then personalised with the Karvonen method, which works from your heart
rate reserve rather than raw percentages of maximum:
Target HR = (HRmax − HRrest) × intensity % + HRrest
Using the reserve matters because two people with the same HRmax but different fitness levels (reflected in
resting heart rate) should not train at the same absolute numbers.
Worked example
Age 30, resting heart rate 65 bpm, classic formula: HRmax = 220 − 30 =
190 bpm, so the reserve is 190 − 65 = 125 bpm. Zone 2 (60–70%) becomes
0.60 × 125 + 65 = 140 bpm up to 0.70 × 125 + 65 = 153 bpm — a comfortable,
conversational effort. With Tanaka, HRmax would be 208 − 21 = 187 bpm and every zone shifts slightly lower.
What each zone is for
- Zone 1 — Very light (50–60%): warm-up, cool-down and recovery days.
- Zone 2 — Light (60–70%): aerobic base and fat metabolism; you can hold a conversation.
- Zone 3 — Moderate (70–80%): aerobic fitness; breathing harder, talking in short sentences.
- Zone 4 — Hard (80–90%): anaerobic threshold work — tempo runs and intervals.
- Zone 5 — Maximum (90–100%): short sprints and peak efforts, sustainable for minutes at most.
Age formulas are population averages with real spread between individuals — if training precision matters to you,
a supervised max test or lactate assessment will beat any formula.
Frequently asked questions
Which zone burns the most fat?
Zone 2 (60–70% intensity) is nicknamed the "fat-burning zone" because the highest proportion of calories burned there comes from fat. Higher zones still burn more total calories per minute, so for weight management overall calorie burn matters more than the zone label.
What is the Karvonen method?
It scales intensity to your heart rate reserve — the gap between maximum and resting heart rate: target = (HRmax − HRrest) × intensity % + HRrest. Because it accounts for your resting rate, it personalises zones better than taking simple percentages of HRmax alone.
Which formula for maximum heart rate should I use?
"220 − age" is the classic rule of thumb; Tanaka (208 − 0.7 × age) came from a larger analysis and is generally more accurate, especially over 40, where the classic formula underestimates HRmax. Both are population averages — a real max test or lab assessment is more accurate for an individual.
How do I measure my resting heart rate?
Take your pulse for 60 seconds first thing in the morning before getting out of bed, or use a wearable’s overnight average. Typical adult values are 60–80 bpm; endurance-trained people are often in the 40s and 50s.
How much time should I spend in each zone?
A common recommendation for endurance training is roughly 80% of weekly training time easy (zones 1–2) and 20% hard (zones 4–5), with zone 3 used sparingly. Beginners should build a base in zones 1–2 before adding high-intensity work.
This tool provides general health information, not medical advice. Consult a healthcare professional before making decisions based on it.