Rex says
Same equations the textbooks use — just way less awkward. Pop in your stats and I'll tell you what the number actually means for you.
Try a scenario
Click to load — tweak from there.Inputs
Result
Estimated max heart rate
184
Zone 2 — endurance base
134–146 bpm
Zone 3 — tempo
146–159 bpm
Zone 4 — threshold
159–171 bpm
Zone 5 — VO2 max
171–184 bpm
Zone 1 — recovery
122–134 bpm
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter age.
- 2Enter resting heart rate (bpm).
- 3Enter known max hr (0 to estimate) (bpm).
- 4Read your estimated max heart rate on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
Zones based on heart rate reserve (max minus resting) are far more personal than plain percentage-of-max, especially for well-trained athletes with low resting rates.
Worked example
Using the values the calculator loads with:
Inputs
- Age: 35
- Resting heart rate: 60 bpm
- Known max HR (0 to estimate): 0 bpm
Results
- Estimated max heart rate: 184
- Zone 2 — endurance base: 134–146 bpm
- Zone 3 — tempo: 146–159 bpm
- Zone 4 — threshold: 159–171 bpm
- Zone 5 — VO2 max: 171–184 bpm
- Zone 1 — recovery: 122–134 bpm
What each field means
Inputs
- Age
- The age used in the calculation. Starts at 35 so you have a working example on load. Accepted range: 10–100.
- Resting heart rate (bpm)
- The resting heart rate used in the calculation, measured in bpm. Starts at 60 bpm so you have a working example on load. Accepted range: 30–110 bpm.
- Known max HR (0 to estimate) (bpm)
- The known max hr (0 to estimate) used in the calculation, measured in bpm. Starts at 0 bpm so you have a working example on load. Accepted range: 0–230 bpm.
Results
- Estimated max heart rate
- Returned as a whole number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Zone 2 — endurance base
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Zone 3 — tempo
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Zone 4 — threshold
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Zone 5 — VO2 max
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Zone 1 — recovery
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the training heart rate zone calculator work?
Zones based on heart rate reserve (max minus resting) are far more personal than plain percentage-of-max, especially for well-trained athletes with low resting rates. The underlying maths is: Target HR = ((Max − resting) × intensity%) + resting.
What do I need to enter?
3 values: age, resting heart rate, and known max hr (0 to estimate). Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the estimated max heart rate result mean?
It is returned as a whole number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Population formulas describe averages; individual bodies vary, especially at the extremes of height, age, or muscle mass.
Who is this tool for?
It's built for anyone tracking a health or training target and wanting the standard formula applied correctly, without a signup or an app.
Accuracy and limitations
- Population formulas describe averages; individual bodies vary, especially at the extremes of height, age, or muscle mass.
- Results do not account for medical conditions, medication, or pregnancy.
- Use this as a directional reference, not a diagnosis — talk to a clinician before acting on it.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Heart Rate Zone Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/heart-rate-zones
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/heart-rate-zones" target="_blank" rel="noopener">Heart Rate Zone Calculator — RevenueLab</a> (2026).</p>
Source: [Heart Rate Zone Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/heart-rate-zones) (2026).