Heart-rate zone tool

Heart Rate Zones Calculator

Choose a model and enter HRmax/resting HR or LTHR to generate non-overlapping heart-rate zones.

HEART RATE ZONES

Calculator

Enter your values and generate zone boundaries in bpm.

Inputs

Generate heart-rate zones using a model and your heart-rate benchmarks.

Zone model

5 zones

Max HR (bpm)

Use a lab test or a careful field test when healthy.

Resting HR (bpm)

Best measured upon waking, before getting out of bed.

Boundaries are assigned to the higher zone so ranges do not overlap after rounding.

Zones

Enter the required values to see zones.

Zone	%	bpm
Enter values to generate zones.

Training Zones Explained

5 zones — what each zone is for.

Z1 Warm Up

Very easy. Warm-up, cool-down, and recovery work with minimal stress.

Z2 Fat Burn

Easy aerobic. Builds endurance and supports high-volume training.

Z3 Aerobic

Steady moderate. Improves aerobic power and durable pace/effort.

Z4 Anaerobic

Hard. Raises threshold-like tolerance and sustainable hard efforts.

Z5 VO2 Max

Very hard. Short intervals and surges that stress VO2 and anaerobic systems.

How to use heart-rate zones

Choose the benchmark you know

Use HRR if you know resting HR and HRmax, LTHR if you have a threshold test, or Max HR for a quick setup.

Enter your values

Add HRmax, resting HR, or LTHR as required by the selected model, then calculate the non-overlapping bpm ranges.

Apply and refine

Use the zones as intensity targets, then adjust when new tests, fatigue, or sport-specific data change your benchmarks.

What are heart-rate zones?

For athletes turning heart-rate benchmarks into training targets.

Heart-rate zones split HRmax, heart-rate reserve, or LTHR into practical intensity ranges. They help you separate recovery, aerobic, tempo, threshold, VO2, and anaerobic work while accounting for the heart-rate benchmark you actually know.

FAQ

Do HR zones change over time?

Yes. Resting HR and LTHR can shift with training and fatigue. Re-check your values periodically and adjust zones as needed.

Which HR zone model should I use?

If you have resting HR and HRmax, Karvonen (HRR) is a good default. If you have a reliable LTHR estimate, Friel can be more actionable. If you only know HRmax, use the Max HR model.

Why do my zone boundaries differ by 1 bpm?

This tool rounds bpm values and assigns boundaries to the higher zone so output ranges do not overlap, which can create a 1 bpm difference.

Models

Choose the model that matches the data you have and your training style.

Karvonen (HRR)

A strong default model that uses heart-rate reserve (HRR) from HRmax and resting HR.

Friel (LTHR)

A threshold-based model anchored on lactate-threshold heart rate (LTHR), with a more granular 7-zone structure.

Max HR (MHR)

A simple model based on percentages of max heart rate (MHR) when that is the only benchmark you have.

Keep calibrating your intensity targets

Estimate max heart rate for load zones Calculate power training load zones Calculate VDOT for running load targets

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