Heart Rate Zone Calculator

Calculate your 5 heart rate zones using the Karvonen method or %HRmax

Your heart rate data

Measured in the morning, lying down, for 1 minute

Heart rate reserve : 130 bpm

Your 5 heart rate zones

Z1
Active recovery
Very light effort, recovery, warm-up and cool-down
125 – 138
50% – 60% FCR
Z2
Aerobic endurance
Training base, develops aerobic system, burns fat
138 – 151
60% – 70% FCR
Z3
Tempo / Active endurance
Moderate effort, improves endurance and cardiovascular efficiency
151 – 164
70% – 80% FCR
Z4
Threshold / Resistance
Hard effort, pushes lactate threshold, builds speed
164 – 177
80% – 90% FCR
Z5
VO2max / Power
Maximum effort, develops maximal aerobic power, short intervals
177 – 190
90% – 100% FCR

Overview

125-138
138-151
151-164
164-177
177-190
Z1
Z2
Z3
Z4
Z5

Understanding aerobic endurance

Zone 2 is the key to running progress. Discover why 80% of your training should be done at easy aerobic effort.

Read our complete guide on fundamental endurance

What is a heart rate zone?

Heart rate zones are intensity ranges defined as a percentage of your maximum heart rate (HRmax) or heart rate reserve (HRR). They help structure your training by targeting specific physiological adaptations: recovery, aerobic endurance, lactate threshold, or maximal power. Knowing your zones is essential for effective progress while avoiding overtraining.

The Karvonen method: more precise with heart rate reserve

The Karvonen formula uses your heart rate reserve (HRR = HRmax - resting HR) to calculate more personalized zones. The formula is: target HR = (HRR × % intensity) + resting HR. This method is more accurate than simple %HRmax because it accounts for your fitness level (reflected by your resting HR). A runner with a low resting HR will have slightly different zones than a beginner.

How to measure your maximum heart rate?

The most reliable method is a lab stress test. Alternatively, you can do a field test: after a 15-minute warm-up, run 3 × 3 minutes at maximum intensity with 2 minutes recovery. Your highest recorded HR will be close to your HRmax. The Tanaka formula (208 - 0.7 × age) gives an estimate, but individual variation is significant (±10 bpm). Measure your resting HR in the morning, lying down, for 1 minute.

Frequently asked questions

What's the difference between Karvonen and %HRmax?

The Karvonen method uses your HR reserve (HRmax - resting HR) and gives more precise zones as it accounts for your fitness. The %HRmax method is simpler (direct % of HRmax) but less personalized. If you know your resting HR, prefer Karvonen.

How do I find my maximum heart rate?

A lab stress test is the gold standard. In practice, a field test (3 × 3 min all-out after warm-up) or the Tanaka formula (208 - 0.7 × age) give a good approximation. Note: the formula can vary by ±10 bpm between individuals.

Which zone should I run in most often?

Most of your training (70-80%) should be in zone 2 (aerobic endurance). This zone builds your aerobic base, improves fat utilization, and allows recovery while progressing. Zones 4-5 represent 10-20% for quality sessions.

Why is my resting heart rate important?

Resting HR reflects your cardiovascular fitness. The lower it is, the more efficient your heart. It allows the Karvonen method to personalize your zones. It naturally decreases with training: a regular runner can reach 45-55 bpm.