Target Heart Rate Calculator
Calculate your five heart-rate training zones by age using the Karvonen method or simple percentage of maximum heart rate.
About the Target Heart Rate Calculator
This target heart rate calculator turns your age — and optionally your resting heart rate — into the five standard training zones, from easy warm-up effort to maximal intervals. It estimates maximum heart rate as 220 − age, then builds the zones with either a simple percentage of max or the more personalised Karvonen method.
The Karvonen formula works on your heart-rate reserve: target = (max HR − resting HR) × intensity + resting HR. Because it anchors the zones to your actual resting rate, two 35-year-olds with resting rates of 50 and 75 bpm get meaningfully different — and more accurate — zone boundaries than the plain percentage method gives.
Zone training is how endurance programs control effort: zone 2 builds aerobic base, zones 3–4 push threshold, zone 5 develops top-end power. The 220 − age rule is a population average with real individual spread, so treat the zones as a starting point and adjust to perceived effort.
How to Use the Target Heart Rate Calculator
- 1Enter your age.
- 2Choose the Karvonen method and enter your resting heart rate, or use simple % of max.
- 3Read your estimated maximum heart rate and the five training zones in bpm.
- 4Target the zone that matches your session goal — base, tempo or intervals.
Frequently Asked Questions
How are heart-rate zones calculated? A worked example
A 35-year-old has an estimated max of 220 − 35 = 185 bpm. With a resting rate of 60, heart-rate reserve is 125. Zone 2 (60–70%) by Karvonen runs from 125 × 0.6 + 60 = 135 to 125 × 0.7 + 60 = 147.5 bpm. The simple method would give 111–129.5 bpm — noticeably lower.
What is the Karvonen method and why is it better?
It scales intensity across your heart-rate reserve (max minus resting) instead of raw max, so your fitness level is built in: a lower resting rate — a marker of aerobic fitness — shifts every zone accordingly. Percent-of-max zones ignore resting rate entirely and tend to understate effort for fit individuals.
How accurate is the 220 − age formula?
It's a population average with a standard deviation of roughly 10–12 bpm — plenty of healthy 40-year-olds max at 170 or 195 rather than 180. Alternatives like Tanaka (208 − 0.7 × age) fit older adults slightly better. For precision, a field max test or lab test beats any formula.
Which zone burns the most fat?
Zone 2 (60–70%) burns the highest proportion of calories from fat and is the backbone of endurance training, but higher zones burn more total calories per minute. For weight management, total energy expenditure matters more than the fuel mix — the best zone is the one you can sustain consistently.
How do I measure my resting heart rate?
Immediately after waking, before coffee or getting up: count your pulse for 60 seconds, or let a wearable average your sleeping rate. Typical adult values run 60–80 bpm; endurance-trained people often sit in the 40s–50s. Measure over several mornings and use the average.