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Hndy Tools

Target Heart Rate Calculator

Calculate your personalised exercise heart rate zones using the Karvonen formula

Heart Rate
Fitness
Karvonen
Training Zones

Your Details

Between 10 and 120

Measure in the morning before rising

About the Target Heart Rate Calculator

This calculator uses the Karvonen formula to determine your personalised exercise heart rate zones. Unlike simpler methods that only use a percentage of your maximum heart rate, the Karvonen method factors in your resting heart rate — making the results more accurate and tailored to your fitness level.

Maximum heart rate is estimated using the Tanaka formula (208 − 0.7 × age), which research has shown to be more accurate across all age groups than the traditional 220 − age formula. Your Heart Rate Reserve (HRR) is then calculated as the difference between your estimated max and resting heart rates.

The five training zones — from easy recovery through to peak VO₂ max efforts — are widely used by coaches, athletes, and fitness enthusiasts. Pair this tool with our Resting Heart Rate Fitness Score to evaluate your overall cardiovascular health, or check your VO₂ Max Estimator to understand your aerobic capacity.

All processing happens entirely in your browser — no data is sent to any server. Your health information stays completely private.

Frequently Asked Questions (FAQ)

What is target heart rate and why does it matter?
Target heart rate (THR) is the ideal heart rate range during exercise to get the most benefit from your workout. Training in the correct zone helps you burn fat efficiently, build cardiovascular endurance, or improve peak performance — depending on your goal. Use our Resting Heart Rate Fitness Score tool to assess your baseline cardiovascular health.
What is the Karvonen formula?
The Karvonen formula calculates target heart rate using your Heart Rate Reserve (HRR), which is the difference between your maximum heart rate and resting heart rate. The formula is: THR = (HRR × intensity%) + Resting HR. It is more personalised than simply using a percentage of max HR because it accounts for your fitness level through resting heart rate.
How do I find my resting heart rate?
Measure your pulse first thing in the morning before getting out of bed. Count the beats for 60 seconds (or for 15 seconds and multiply by 4). A typical resting heart rate for adults is 60–100 bpm, while well-trained athletes may range from 40–60 bpm. For a detailed evaluation, try our Resting Heart Rate Fitness Score tool.
What heart rate zone is best for weight loss?
Zone 2 (60–70% HRR) is often called the "fat burn zone" because a higher proportion of calories burned come from fat. However, higher zones burn more total calories. A mix of Zone 2 and Zone 3 training is generally most effective for weight loss. You can also track your body fat percentage to monitor progress.
Is this calculator accurate for everyone?
This calculator uses the Tanaka formula (208 − 0.7 × age) for max HR, which is more accurate than the older 220 − age formula. However, individual max heart rates can vary by ±10–15 bpm. People on beta-blockers or with cardiac conditions should consult a physician. The Karvonen method is widely regarded as one of the most reliable intensity-estimation methods for healthy individuals.
Is my data safe?
Absolutely. All calculations happen entirely in your browser. No data is sent to any server, stored, or tracked. Your health information remains private at all times.

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