Plot No. 49 · Health & Fitness
Target Heart Rate Zone Calculator
Find your training heart rate zones from your age, and optionally your resting heart rate. Maximum heart rate is roughly 220 minus your age. The calculator then maps that onto fat-burn, cardio and peak zones, using the Karvonen reserve method when you enter a resting rate.
Zones use the Karvonen heart rate reserve method from your resting rate. These are estimates, not medical advice.
The link saves your inputs so you can bookmark or share this exact result.
How your heart rate zones are worked out
Your maximum heart rate is estimated as 220 minus your age, so a 30 year old has a maximum of about 190 beats per minute. Training zones are then bands within that maximum: a fat-burn zone at 50 to 70 percent, a cardio zone at 70 to 85 percent, and a peak zone at 85 to 95 percent. Each band tells you roughly how hard you are working.
If you enter a resting heart rate, the calculator switches to the Karvonen method. Instead of a flat percentage of your maximum, Karvonen uses your heart rate reserve, the gap between maximum and resting. A target equals reserve times the intensity, plus your resting rate. People with a low resting heart rate get higher, more personal zones this way.
How to use the target heart rate calculator
- Enter your age to set your estimated maximum heart rate.
- Optionally enter your resting heart rate, measured first thing in the morning, to switch to the Karvonen method.
- Read the beats-per-minute range for each zone and pick the one that matches your session.
Worked examples
30 year old, resting rate 60
Inputs: Age 30, resting heart rate 60 bpm
Result: Maximum 190 bpm. Karvonen fat-burn zone is 125 to 151 bpm, cardio 151 to 171 bpm, and peak 171 to 184 bpm.
Same age, no resting rate entered
Inputs: Age 30, resting heart rate left at 0
Result: Maximum 190 bpm with simple percentages: fat-burn 95 to 133 bpm, cardio 133 to 162 bpm, peak 162 to 181 bpm, lower than the Karvonen bands.
Limitations and common mistakes
Edge cases and limitations
- The 220 minus age formula is a rough average and can be 10 to 15 beats off your true maximum.
- Medications such as beta blockers lower heart rate and make these zones unreliable.
- Zones are training guides, not medical advice; stop and seek help if you feel unwell during exercise.
Common mistakes
- Measuring resting heart rate after coffee or activity rather than at rest, which pushes the Karvonen zones too high.
- Living in the peak zone every session; most training should sit in the easier fat-burn and cardio bands.
Frequently asked questions
How do I work out my maximum heart rate?
The common estimate is 220 minus your age. For a 30 year old that gives a maximum of about 190 beats per minute. It is a population average, so your true maximum can sit 10 to 15 beats either side.
What is the Karvonen method?
Karvonen uses your heart rate reserve, the gap between your maximum and resting rates, instead of a flat percentage of maximum. A target equals reserve times the intensity, plus your resting rate. It tends to give higher, more personal zones for people with a low resting heart rate.
Which zone should I train in?
The fat-burn zone, around 50 to 70 percent, suits easy and long sessions. The cardio zone, 70 to 85 percent, builds aerobic fitness. The peak zone, 85 to 95 percent, is hard interval work and should be used sparingly.
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