Heart Rate Zone Calculator — Free Karvonen Training Zones

Free heart rate zone calculator using Karvonen method. Find your 5 training zones with max HR and resting HR. 100% client-side. 100% serverless.

🔒 100% Private

⚡ Completely Free

🌐 Runs in Browser

📦 Export Ready

Enter Age — For max HR calculation (220 - age).
Resting HR — Your heart rate at rest (bpm).
Calculate — See 5 training zones with BPM ranges.

Heart Rate Zone Calculator — Karvonen Training Zones

The Heart Rate Zone Calculator uses the Karvonen formula to calculate your 5 personalized training heart rate zones. Unlike simple max HR percentage, Karvonen accounts for your resting heart rate, providing more accurate training targets.

The 5 Training Zones

Zone 1 (50-60%) — Warm Up: Recovery, easy walking, light activity.
Zone 2 (60-70%) — Fat Burn: Optimal fat oxidation, long steady runs.
Zone 3 (70-80%) — Cardio: Endurance building, tempo runs.
Zone 4 (80-90%) — Peak: Speed training, interval workouts.
Zone 5 (90-100%) — VO₂ Max: Maximum effort, sprints.

The Karvonen Formula

Target HR = ((Max HR - Resting HR) × Intensity%) + Resting HR. Max HR is estimated as 220 - age.

Features

5 Zones — Color-coded with BPM ranges.
Purpose Labels — Know what each zone trains.
Karvonen Method — More accurate than basic % of Max HR.

Privacy

All calculations run in your browser.

Frequently Asked Questions

What method is used?

The Karvonen formula: Target HR = ((Max HR - Resting HR) × Intensity%) + Resting HR. More accurate than simple percentage of max HR.

What are the 5 zones?

Zone 1: Warm Up (50-60%), Zone 2: Fat Burn (60-70%), Zone 3: Cardio (70-80%), Zone 4: Peak (80-90%), Zone 5: VO₂ Max (90-100%).

How do I measure resting HR?

Measure your pulse first thing in the morning while still lying down. Count beats for 60 seconds. Average over 3-5 days for accuracy.

Is my data uploaded?

No. All calculations run 100% in your browser.

Heart Rate Zone Calculator — Free Karvonen Training Zones