Heart Rate Zone Calculator
Training in the right heart rate zone is one of the most effective ways to structure your exercise and achieve specific fitness goals. The five-zone model divides your effort from gentle active recovery at the bottom to all-out anaerobic exertion at the top. Each zone produces different physiological adaptations: Zone 2 builds mitochondrial density and fat metabolism; Zones 3 and 4 improve cardiovascular efficiency and lactate threshold; Zone 5 builds peak power and speed. This calculator produces zones using two methods. The simple percentage method uses maximum heart rate (estimated as 220 minus your age) and calculates each zone as a percentage band. The Karvonen method is more precise: it first calculates your heart rate reserve (max HR minus resting HR) and applies percentages to that reserve before adding resting HR back. The Karvonen method is recommended because it accounts for your individual fitness level. Enter your age and, optionally, your resting heart rate for the Karvonen zones.
Formula
Max HR (Fox) = 220 - age
Simple method: Zone low = Max HR * lower%, Zone high = Max HR * upper%
Karvonen method: HRR = Max HR - Resting HR
Target HR = (HRR * intensity%) + Resting HR
Zone 1: 50-60% | Zone 2: 60-70% | Zone 3: 70-80%
Zone 4: 80-90% | Zone 5: 90-100%
Heart Rate Zone Calculator: frequently asked questions
What are heart rate training zones?
Heart rate training zones divide your exercise intensity into five bands based on percentage of maximum heart rate. Zone 1 (50-60%) is very light recovery work. Zone 2 (60-70%) builds aerobic base and fat burning. Zone 3 (70-80%) is aerobic conditioning. Zone 4 (80-90%) is threshold training that improves lactate tolerance. Zone 5 (90-100%) is maximum effort anaerobic work.
What is the Karvonen method?
The Karvonen method, also called the heart rate reserve method, calculates target zones from the difference between your maximum and resting heart rates. This heart rate reserve is multiplied by a percentage and your resting HR is added back. It produces more personalised zones than the simple max HR method because it accounts for your cardiovascular fitness level.
How do I find my maximum heart rate?
The simplest estimate is 220 minus your age (Fox formula). More accurate formulas include Tanaka (208 - 0.7 * age) and Gulati (206 - 0.88 * age, for women). A true maximum heart rate can only be determined by a maximal exercise test, such as a graded treadmill test. Self-test with caution and medical clearance if you have any cardiovascular concerns.
What zone should I train in for fat loss?
Zone 2 (60-70% of max HR) is sometimes called the fat-burning zone because fat is the primary fuel at lower intensities. However, higher-intensity zones burn more total calories per minute, which also contributes to fat loss. Most exercise physiologists recommend a mix of Zone 2 for long steady sessions and higher zones for interval work.
How do I measure my resting heart rate?
Measure your resting heart rate first thing in the morning before getting out of bed. Count your pulse for 60 seconds, or count for 15 seconds and multiply by four. For a more accurate reading, average measurements taken on three consecutive mornings. A typical resting heart rate for adults is 60 to 100 beats per minute; well-trained athletes often measure 40 to 60 bpm.
Official sources
- Karvonen MJ, Kentala E, Mustala O. (1957). "The effects of training on heart rate: a longitudinal study." Annales Medicinae Experimentalis et Biologiae Fenniae, 35(3):307-315.
- American Heart Association: Target Heart Rates
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.