Max Heart Rate Zones Calculator – Fox, Tanaka, Gellish, Miller & Karvonen
This Max Heart Rate Zones Calculator helps you estimate your maximum heart rate and cardio training zones using several popular formulas. These zones can be used to structure running, cycling, gym cardio, interval training, and endurance programs.
All formulas in this tool provide estimates based on large population studies. Individual values can differ, especially for highly trained athletes or people with heart conditions. For safety, always check with a healthcare professional before following any high-intensity training plan.
Heart Rate Zones Explained
Most training plans divide intensity into five heart rate zones. In this calculator, the zones are based on a percentage of your estimated max heart rate or heart rate reserve:
- Zone 1 (50–60%) – Very light effort, recovery and easy warm-up.
- Zone 2 (60–70%) – Light endurance training, comfortable conversational pace.
- Zone 3 (70–80%) – Moderate tempo work, stronger breathing but still sustainable.
- Zone 4 (80–90%) – Hard effort, threshold intervals and race pace for trained athletes.
- Zone 5 (90–100%) – Very hard to all-out, short intervals and sprint work.
Formula 1: Fox 220 − Age
The Fox formula is one of the oldest and most commonly cited estimates of maximum heart rate:
It is easy to remember and widely used, but it can overestimate or underestimate true max heart rate for some people. This calculator uses the Fox formula in the first tab and then creates zones 1–5 as percentages of this value.
Formula 2: Tanaka Formula
The Tanaka formula is based on more recent research and slightly modifies the age relationship:
For many adults, Tanaka often gives a slightly lower max heart rate than the Fox formula. It can be useful if Fox consistently feels too aggressive compared with how you respond in training.
Formula 3: Gellish Formula
The Gellish formula is another research-based approach:
It is similar to Tanaka but gives a slightly different intercept. Using multiple formulas side-by-side can give you a practical range instead of a single exact number.
Formula 4: Miller Formula
The Miller formula provides another way to estimate max heart rate:
Because the slope and intercept differ from the other formulas, Miller can produce higher or lower values depending on age. Comparing all four methods helps you see whether a cluster of results appears around the same heart rate value.
Formula 5: Karvonen Heart Rate Reserve (HRR)
The Karvonen method does not estimate max heart rate directly; instead, it uses heart rate reserve. Heart rate reserve is the difference between your max heart rate and resting heart rate. Training zones are calculated as a percentage of this reserve and then added back to resting heart rate:
Target HR = (Heart Rate Reserve × Intensity%) + Resting HR
This calculator uses the Fox formula (220 − Age) to estimate max heart rate, then combines it with your resting heart rate to calculate personalized zones 1–5. This often matches perceived effort better than simple percentage of max HR.
How to Use the Max Heart Rate Zones Calculator
- Select the formula tab you want to use.
- Enter your age in years. For the Karvonen method, also enter your resting heart rate measured at complete rest.
- Click “Calculate Zones”.
- Review your estimated max heart rate and the bpm ranges for Zones 1–5.
- Use the zones to structure easy, moderate, and hard workouts rather than trying to train at max effort all the time.
How to Measure Resting Heart Rate
For better Karvonen results, measure resting heart rate when you are relaxed, preferably in the morning before getting out of bed:
- Sit or lie down calmly for a few minutes.
- Use a heart rate monitor, fitness tracker, or manually feel your pulse at the wrist or neck.
- Count beats for 30 seconds and double the number, or count for a full minute for greater accuracy.
- Repeat for a few mornings and use the average.
Using Heart Rate Zones in Training
Many endurance programs combine different zones throughout the week. Examples include:
- Zone 1–2: Most easy base training, recovery days and long slow distance workouts.
- Zone 3: Steady tempo runs, strong but controlled efforts to build stamina.
- Zone 4: Threshold intervals and race-specific efforts for trained athletes.
- Zone 5: Very short, intense intervals or sprints for performance and speed.
It is usually not necessary or wise to spend long periods near your maximum heart rate. Instead, use a mix of zones that matches your goals, current fitness, and medical guidance.
Important Safety Note
These formulas provide estimates only. Actual maximum heart rate varies between individuals, and certain medications or medical conditions can change heart rate response. If you have any cardiovascular risk factors, symptoms, or concerns, talk to a doctor or qualified professional before using high-intensity heart rate zones.
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Max Heart Rate Zones FAQs
Frequently Asked Questions About Heart Rate Zones
Understand how max heart rate, training zones, and heart rate reserve work in practical training.
Max heart rate is used to create training zones that guide workout intensity. It helps you target easy, moderate, hard, and very hard efforts safely and consistently.
Each formula comes from a different study with slightly different populations and assumptions. They represent averages, so natural variation between individuals is expected.
Zone 2 is often called the “fat-burning” zone because it uses a higher percentage of fat as fuel, but higher zones can burn more total calories in less time. Both can be useful.
Heart rate monitors sometimes show values above the estimate because formulas are not exact. If you see unusually high readings or feel unwell, reduce intensity and consult a professional.
Zone 5 is very demanding and should generally be used sparingly, often in short intervals, and only when you have a good fitness base and medical clearance if needed.
A heart rate monitor makes zone training easier and more accurate, but you can also combine these estimates with perceived exertion and breathing patterns to guide intensity.