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Heart Rate Zone Calculator

Use this heart rate zone calculator to calculate calculate heart rate training zones from age and resting heart rate.

heart rate zonetrainingfitness

Calculator

Calculate instantly

Calculator Inputs

Choose what you want to calculate, enter realistic values, adjust units where shown, and use the scenario section for repeated-use planning.

Input and Formula Breakdown

This calculator applies the formula Karvonen zone = resting HR + intensity x heart rate reserve. Enter each value with the matching unit, and AZCalculate updates the result instantly.

Age
35
Resting heart rate
60 bpm
Low intensity
60 %
High intensity
80 %
Estimated max HR
185 bpm
Low zone
135 bpm
High zone
160 bpm

Scenario and Comparison

Current

185 bpm

Projected

2,220

Adjusted

203.5

Visual Comparison

Current result185
Projected usage2,220
Comparison scenario203.5

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Trust note

Important estimate

This calculator is informational and should be verified before financial, health, legal, engineering, laboratory, or safety-critical decisions.

High risk contextDifficulty: intermediateConfidence estimate: 87/100Reviewed 2026-05-18Reviewed by: Health content reviewerCalculator vuces-2.1 / Formula vformula-1.03 sources listed

Formula and Explanation

Karvonen zone = resting HR + intensity x heart rate reserve

This calculator applies the formula Karvonen zone = resting HR + intensity x heart rate reserve. Enter each value with the matching unit, and AZCalculate updates the result instantly.

Variable descriptions

age
Age: Age, entered as a known value.
resting(bpm)
Resting heart rate: Resting heart rate measured in bpm, entered as a known value.
intensityLow(%)
Low intensity: Low intensity measured in %, entered as a known value.
intensityHigh(%)
High intensity: High intensity measured in %, entered as a known value.

Formula Notes

  • Use consistent units for values that are multiplied, divided, or compared.
  • Results may be rounded for readability, while the calculator keeps greater precision internally.
  • Real-world measurements and assumptions can introduce small differences from the calculated estimate.

Common uses

  • Plan cardio zones
  • Compare intensity
  • Track workouts

Assumptions

What this calculation assumes

  • Inputs are self-reported and may not capture medical history, medication, age-specific context, or clinical risk.
  • Health ranges are screening references, not diagnoses.
  • Inputs are assumed to describe the same scenario and use compatible units.
  • Results may be rounded for readability.

Avoid mistakes

Quick checks before you rely on the result

  • Treating a screening estimate as a diagnosis.
  • Entering body measurements in the wrong unit system.
  • Mixing units, periods, currencies, or measurement systems without converting first.
  • Rounding intermediate values too early.

Step-by-Step Explanation

Follow the reasoning, not only the final number.

  1. 1

    Set up the calculation

    Enter the known values in the calculator fields.

    Starting with clearly defined values and units prevents the most common calculation errors.

  2. 2

    Work through step 2

    Keep the units consistent with the labels shown beside each input.

    This step transforms the known values into the form required by the formula.

  3. 3

    Work through step 3

    Apply the formula: Karvonen zone = resting HR + intensity x heart rate reserve.

    This step transforms the known values into the form required by the formula.

  4. 4

    Interpret the result

    Review the primary result and supporting values.

    Compare the result with your real-world goal, such as plan cardio zones.

Worked example

Practical heart rate zone calculator example

Known values

  • Age: 35
  • Resting heart rate: 60 bpm
  • Low intensity: 60 %
  • High intensity: 80 %

Calculation

  1. 1. Start with the known values shown for this heart rate zone calculator scenario.
  2. 2. Substitute those values into Karvonen zone = resting HR + intensity x heart rate reserve.
  3. 3. Evaluate the expression and keep the requested unit and rounding.

Result and meaning

Estimated max HR: 185 bpm; Low zone: 135 bpm; High zone: 160 bpm

Calculator guide

About this Heart Rate Zone Calculator

Calculate heart rate training zones from age and resting heart rate. This page includes an interactive calculator, concise formula notes, worked examples, FAQs, related calculators, and practical guidance you can revisit whenever needed.

heart rate zonetrainingfitness

References

Sources used for this calculator

Found something that does not look right?

We work hard to keep every calculator accurate and useful. If you notice a calculation error, missing option, or unclear explanation, please let us know so we can review and correct it promptly.

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Calculator usage

Usage information loads after the calculator is ready.

FAQ

Heart Rate Zone Calculator FAQs

How does the heart rate zone calculator work?+

It uses Karvonen zone = resting HR + intensity x heart rate reserve and calculates the result from the values you enter.

Can I copy or print the result?+

Yes. AZCalculate calculator pages include copy, share, and print actions.

Is this medical advice?+

No. It is an educational estimate and should not replace care from a qualified healthcare professional.

Why can health calculators be different for each person?+

Age, sex, health history, medication, pregnancy, activity level, and body composition can affect interpretation.

How should I use this calculator result?+

Use it as an estimate and compare it with the formula, assumptions, and examples shown on the page.

Why can real-world results differ?+

Real-world inputs can include local rules, changing rates, measurement tolerances, and conditions outside the core formula.

What information do I need for the heart rate zone calculator?+

Enter the known values requested by the calculator. Use the unit selectors where available and make sure the values describe the same scenario.

How accurate is the heart rate zone calculator?+

The calculator follows the formula shown on this page. Accuracy depends on the values, units, assumptions, and rounding used in your scenario.

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Heart Rate Zone Calculator - AZCalculate | AZCalculate