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Heart Rate Zone Training Calculator

Calculate your 5 heart rate training zones with the Karvonen formula. Enter age and resting heart rate for targeted workouts.

Sources: Karvonen M.J. et al. -- The Effects of Training on Heart Rate, 1957 · ACSM -- Guidelines for Exercise Testing and Prescription

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How the Heart Rate Zone Calculator Works

This tool calculates your 5 personalized heart rate zones using the Karvonen formula, the most accurate method among prediction-based formulas. Each zone corresponds to a specific training goal.

The Karvonen Formula

Target HR = Resting HR + (% intensity x Heart Rate Reserve)

Where: Heart Rate Reserve = Max HR - Resting HR

The 5 Zones Explained

Zone 1 -- Active Recovery (50-60%): walking, warm-up. You can talk without any difficulty.

Zone 2 -- Aerobic Base (60-70%): slow running, light cycling. Builds aerobic base and burns fat proportionally. You can speak in complete sentences.

Zone 3 -- Intense Aerobic (70-80%): sustained running. Improves aerobic capacity and endurance. You can say only short sentences.

Zone 4 -- Anaerobic Threshold (80-90%): interval training, repeats. Improves speed and lactate tolerance. You can say only a few words.

Zone 5 -- Maximum Intensity (90-100%): sprints, bursts. Sustainable only for seconds or minutes. You cannot speak.

How to Use Zones in Training

A balanced training program should distribute volume according to the 80/20 rule: 80% of time in Zone 1-2 (low intensity) and 20% in Zone 3-5 (high intensity).

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Frequently Asked Questions

How are heart rate zones calculated?▼
Heart rate zones are calculated with the Karvonen formula: Target HR = Resting HR + (percentage x heart rate reserve), where heart rate reserve = Max HR - Resting HR. Max HR is estimated with 220 - age. This method is more precise than simple percentage of max HR.
What is the fat-burning zone?▼
The "fat-burning zone" corresponds to Zone 2 (60-70% of heart rate reserve). At this intensity, the body uses a greater percentage of fat as energy. However, higher intensity zones (3-4) burn more total calories and more fat in absolute terms per unit of time.
Is the 220-age formula accurate?▼
The 220-age formula is an estimate with a margin of error of +/-10-12 bpm. It works for most people but can be imprecise for trained athletes, elderly, or people with particular conditions. For a precise measurement of max HR, a stress test in a medical setting is the best option.