Heart Rate Zone Calculator | Training Zones by Age, HRmax & Resting HR

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Heart Rate Zone Calculator

Age

yrs

Used to estimate maximum heart rate from common age-based equations if you do not enter a measured HRmax.

Primary Goal

🎯

Used to highlight the most relevant zone focus.

Heart Rate Inputs

Resting Heart Rate

bpm

Required only for Karvonen heart rate reserve mode.

Measured Max Heart Rate

bpm

Optional. Leave blank to use estimated max heart rate from age.

HRmax Formula

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.

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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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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 1	50% to 60%	Recovery and very easy effort
Zone 2	60% to 70%	Easy aerobic and base building
Zone 3	70% to 80%	Moderate steady work
Zone 4	80% to 90%	Threshold and hard sustained work
Zone 5	90% to 100%	Intervals and very hard efforts

Zone

Range

Typical Focus

Zone 1

50% to 60%

Recovery and very easy effort

Zone 2

60% to 70%

Easy aerobic and base building

Zone 3

70% to 80%

Moderate steady work

Zone 4

80% to 90%

Threshold and hard sustained work

Zone 5

90% 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. Use the result as a training estimate. Heart rate zones depend on age, resting heart rate, estimated maximum heart rate, medication, fatigue, hydration, heat, fitness level, and measurement accuracy. Compare the result with perceived effort and seek professional guidance if you have symptoms or a heart condition.

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. Use the result as a training estimate. Heart rate zones depend on age, resting heart rate, estimated maximum heart rate, medication, fatigue, hydration, heat, fitness level, and measurement accuracy. Compare the result with perceived effort and seek professional guidance if you have symptoms or a heart condition.

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. Use the result as a training estimate. Heart rate zones depend on age, resting heart rate, estimated maximum heart rate, medication, fatigue, hydration, heat, fitness level, and measurement accuracy. Compare the result with perceived effort and seek professional guidance if you have symptoms or a heart condition.

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. Use the result as a training estimate. Heart rate zones depend on age, resting heart rate, estimated maximum heart rate, medication, fatigue, hydration, heat, fitness level, and measurement accuracy. Compare the result with perceived effort and seek professional guidance if you have symptoms or a heart condition.

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. Use the result as a training estimate. Heart rate zones depend on age, resting heart rate, estimated maximum heart rate, medication, fatigue, hydration, heat, fitness level, and measurement accuracy. Compare the result with perceived effort and seek professional guidance if you have symptoms or a heart condition.