Heart Rate Zone Calculator
Free heart rate zone calculator. Enter your age and resting heart rate to get your max HR and five training zones using the Karvonen formula. For cardio and fat-burn training.
Uses the Karvonen formula: target HR = (max HR − resting HR) × intensity + resting HR, with max HR estimated as 220 − age.
About the Heart Rate Zone Calculator
Our free heart rate zone calculator works out your five training zones from your age and resting heart rate. It estimates your maximum heart rate as 220 minus age, then applies the Karvonen formula — target HR = (max HR − resting HR) × intensity + resting HR — to give the bpm range for each zone: very light recovery, light fat burn, moderate aerobic, hard anaerobic, and maximum VO2. Whether you train with a chest strap or a wrist monitor, knowing your zones keeps easy days easy and hard days hard. Everything runs in your browser — instant, private, no signup.
Features
- Five zones from age and resting HR
- Uses heart-rate reserve with an age-based maximum estimate
- Shows max, fat-burn and cardio ranges
- bpm ranges for every intensity
- 100% client-side and private — instant results, no signup
How to use this tool
The Heart Rate Zone Calculator works right in your browser — no signup, no installation. Follow these steps:
- Enter your age.
- Enter your resting heart rate (bpm).
- Read your max heart rate.
- Use the zone ranges to guide training.
Frequently asked questions
What is the Karvonen formula?
The Karvonen formula sets your target heart rate as (max HR − resting HR) × intensity + resting HR. Because it factors in your resting heart rate, it personalises each zone better than a simple percentage of max HR alone.
How is maximum heart rate estimated?
The common estimate is 220 minus your age. It is a rough population average — your true max can vary by 10–15 bpm — but it works well for setting training zones.
Which zone burns the most fat?
Zone 2 (about 60–70% of reserve) is called the fat-burn zone because a higher share of the energy comes from fat, though total calories matter most for weight loss. Zone 2 is also where you build aerobic base.
How do I find my resting heart rate?
Measure it first thing in the morning before getting out of bed: count pulses for 60 seconds, or use a fitness tracker’s overnight reading. Most adults sit between 60 and 100 bpm; trained athletes are often lower.
Is this heart rate zone calculator free?
Yes, completely free with no signup. All maths runs in your browser — nothing is uploaded or tracked.
Using the results
The Heart Rate Zone Calculator calculates an estimate from the measurements you enter. Read the formula and limitations alongside the result; an estimate is not a diagnosis.