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Home› Health Calculators› Fitness & Performance› Heart Rate Zone Calculator

Heart Rate Zone Calculator
with HRmax and Karvonen Zones

Calculate Zone 1 to Zone 5 training ranges using either simple maximum heart rate percentages or heart rate reserve with resting heart rate.

❤️
Heart Rate Zone Calculator
yrs
Used to estimate maximum heart rate from common age-based equations if you do not enter a measured HRmax.
🎯
Used to highlight the most relevant zone focus.
Heart Rate Inputs
bpm
Required only for Karvonen heart rate reserve mode.
bpm
Optional. Leave blank to use estimated max heart rate from age.
fx
Used only when measured max heart rate is not entered.
Method note
Simple percentage mode calculates each zone as a percentage of maximum heart rate. Karvonen mode uses heart rate reserve and adds resting heart rate back to each zone boundary.
Primary Training Focus
—
recommended zone based on selected goal
Max Heart Rate Used
—
measured or age-based estimate
Resting Heart Rate
—
used in Karvonen mode
Heart Rate Reserve
—
max heart rate minus resting heart rate
Method Used
—
simple max percentage or Karvonen HRR
Zone 1
—
Recovery and very easy effort.
Zone 2
—
Easy aerobic and endurance base.
Zone 3
—
Moderate steady work and aerobic build.
Zone 4
—
Threshold and hard sustained work.
Zone 5
—
Very hard efforts and interval work.
Input summary
Age—
Goal—
Measured HRmax—
HRmax formula—
Method summary
Method—
Resting HR—
HRmax used—
Heart rate reserve—
Heart Rate Training Zone Table
Zone Intensity Range Use Case
Zone Calculation Breakdown
Method used—
Age—
Goal—
Maximum heart rate used—
Resting heart rate—
Heart rate reserve—
Zone 1—
Zone 2—
Zone 3—
Zone 4—
Zone 5—
This calculator provides general training estimates and is not medical advice. Estimated maximum heart rate formulas are approximations and may differ from directly measured values.
✦ Cal, AI Explanation
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💡 Heart Rate Zone Notes

Simple percentage mode uses fixed percentages of maximum heart rate.
Karvonen mode uses heart rate reserve, which adjusts zones using resting heart rate.
Lower zones are usually associated with easier aerobic work, while higher zones are used for harder efforts.
Estimated maximum heart rate formulas are convenient, but measured values can differ.
Zone labels and boundaries can vary slightly between coaching systems.

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Related Guides

Heart Rate Zones Explained→ Karvonen vs Max Heart Rate→ Zone 2 Training Guide→

How heart rate zones are calculated

Heart rate zone systems divide exercise intensity into ranges. The simplest method uses a percentage of maximum heart rate. A more individualized method, Karvonen heart rate reserve, uses both maximum and resting heart rate.

This calculator supports both approaches. If you enter a measured maximum heart rate, that value is used. Otherwise, the calculator estimates maximum heart rate from age using a common formula.

Core formulas

Simple zone boundary = maximum heart rate × target percentage
Heart rate reserve = maximum heart rate − resting heart rate
Karvonen zone boundary = (heart rate reserve × target percentage) + resting heart rate
Zone percentages in this calculator use a common five-zone structure from 50% to 100% intensity.

Zone structure used here

This calculator uses a five-zone model. Zone 1 is the easiest range and Zone 5 is the hardest. Each zone corresponds to a different intensity bracket and is commonly used for different training purposes.

Zone Range Typical Focus
Zone 150% to 60%Recovery and very easy effort
Zone 260% to 70%Easy aerobic and base building
Zone 370% to 80%Moderate steady work
Zone 480% to 90%Threshold and hard sustained work
Zone 590% to 100%Intervals and very hard efforts

When simple max percentage and Karvonen differ

Simple max percentage treats two people with the same maximum heart rate the same way, even if their resting heart rates differ. Karvonen heart rate reserve adjusts for resting heart rate, so the zone boundaries can shift upward or downward.

That makes Karvonen useful when you want a zone system that reflects both maximum and resting heart rate rather than only maximum heart rate.

Frequently Asked Questions

What is the difference between simple max percentage and Karvonen?+
Simple max percentage calculates zones directly from maximum heart rate. Karvonen first calculates heart rate reserve by subtracting resting heart rate from maximum heart rate, then adds resting heart rate back into each zone boundary.
Should I use measured max heart rate or estimated max heart rate?+
If you have a reliable measured maximum heart rate, it is usually more specific to you than an age-based estimate. Age-based formulas are practical approximations when measured data is not available.
Why is resting heart rate needed for Karvonen?+
Because Karvonen uses heart rate reserve, which is maximum heart rate minus resting heart rate. Resting heart rate changes the size of that reserve and therefore shifts the zone boundaries.
Which zone is best for endurance training?+
In many common zone systems, Zone 2 is often associated with easy aerobic endurance work. Zone 3 and above are generally harder and are used for different kinds of training emphasis.
Are heart rate zones exact?+
No. They are structured training estimates. Maximum heart rate formulas, resting heart rate variation, device differences, and different coaching systems can all change the precise ranges.