Target Heart Rate Calculator

Why Train with Heart Rate Zones?

Not all exercise is created equal. The effectiveness of your workout depends largely on the intensity, and the best way to measure intensity is through your heart rate. This Target Heart Rate Calculator helps you identify your personal "Target Heart Rate Zones." Training in specific zones allows you to aim for specific results—whether that's burning fat, building endurance, or increasing your sprinting speed—without overtraining or undertraining.

Understanding the Calculation Methods

This calculator uses two different formulas depending on the data you provide.

1. The Standard Method (Haskell & Fox)

This is the simplest method, based solely on your age.

• Step 1: Calculate Maximum Heart Rate (MHR) = 220 - Age.
• Step 2: Calculate zones as a simple percentage of MHR (e.g., 50% of MHR).

Note: While widely used, this formula can be less accurate for very fit individuals or older adults.

2. The Karvonen Method (Advanced)

If you enter your Resting Heart Rate (RHR), the calculator automatically switches to the Karvonen formula. This is considered the "gold standard" for athletes because it takes your fitness level into account.

• Heart Rate Reserve (HRR) = Maximum Heart Rate - Resting Heart Rate.
• Target Zone Formula: (HRR × Intensity %) + Resting Heart Rate.

By factoring in your RHR, the zones are adjusted to reflect your true cardiovascular capacity.

Detailed Guide to Heart Rate Zones

Zone 1: Very Light (50-60%)

Best for: Warming up, cooling down, and active recovery.
This zone increases blood flow to muscles to aid in recovery. You should be able to hold a full conversation easily.

Zone 2: Light / Fat Burn (60-70%)

Best for: Weight loss and building basic endurance.
In this zone, your body prefers to use fat as its primary fuel source. It feels comfortable, and you can sustain it for a long time. If your goal is weight loss, combine this with a caloric deficit determined by our Calorie Calculator.

Zone 3: Moderate / Aerobic (70-80%)

Best for: Improving cardiovascular fitness and stamina.
This is the "sweet spot" for many runners. It strengthens your heart and lungs. Breathing becomes heavier, but you can still speak in short sentences. To calculate your running pace for this zone, try our Pace Calculator.

Zone 4: Hard / Anaerobic (80-90%)

Best for: Increasing high-speed endurance and lactate tolerance.
The body shifts to burning glycogen (carbs) for fuel because it needs energy faster than oxygen can be supplied. This zone is uncomfortable and sustainable for only short periods (e.g., 10-20 minutes).

Zone 5: Maximum (90-100%)

Best for: Sprinting and neuromuscular power.
This is your peak effort. It can only be sustained for a few seconds to a couple of minutes. It is very taxing and should be used sparingly by experienced athletes.