Heart Rate Zone Calculator
Five training zones from your max and resting heart rate.
Enter your values
Enter the age in years.
Enter the resting heart rate in bpm.
Enter the known max hr (optional) in bpm.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Estimated max heart rate
- 184 bpm
- Heart rate reserve
- 124 bpm
- Zone 2 (fat-burning base)
- 134 – 146 bpm
| Zone | Range | Purpose |
|---|---|---|
| Zone 1 — recovery | 122 – 134 bpm | recovery |
| Zone 2 — endurance | 134 – 146 bpm | endurance |
| Zone 3 — tempo | 146 – 159 bpm | tempo |
| Zone 4 — threshold | 159 – 171 bpm | threshold |
| Zone 5 — VO2 max | 171 – 184 bpm | VO2 max |
Quick answer
Karvonen zones use heart rate reserve: target = resting + intensity × (max − resting), which is more accurate than percentage of max alone.
Target HR = HRrest + %·(HRmax − HRrest)
At a glance
| What it does | Five training zones from your max and resting heart rate. |
|---|---|
| Category | Health |
| Inputs needed | Age, Resting heart rate, Known max HR (optional) |
| Formula | Target HR = HRrest + %·(HRmax − HRrest) |
| Cost | Free — no sign-up, no download |
How to use the Heart Rate Zone Calculator
- 1Enter your age and resting heart rate.
- 2Add a lab-tested max HR if you have one.
- 3Train inside the zone that matches your session.
Inputs explained
- Age(years)
- Enter the age in years.
- Resting heart rate(bpm)
- Enter the resting heart rate in bpm.
- Known max HR (optional)(bpm)
- Enter the known max hr (optional) in bpm.
Frequently asked questions
Why 208 − 0.7×age?
The Tanaka formula predicts max heart rate more accurately across ages than the older 220 − age rule.
How do I find resting HR?
Measure first thing in the morning before getting up, over three consecutive days, and take the average.
What do I need to enter into the Heart Rate Zone Calculator?
Just 3 values: age, resting heart rate, known max hr (optional). Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Heart Rate Zone Calculator work out the answer?
Karvonen zones use heart rate reserve: target = resting + intensity × (max − resting), which is more accurate than percentage of max alone. It applies the formula Target HR = HRrest + %·(HRmax − HRrest) and shows the working so you can check each step by hand.
Is the Heart Rate Zone Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.