Target Heart Rate Zones

Calculate your training zones using the Karvonen formula, which factors in your resting heart rate for higher accuracy.

JavaScript is disabled. To calculate manually:
1. Max HR = 220 - Age
2. Heart Rate Reserve (HRR) = Max HR - Resting HR
3. Target Zone = (HRR × Intensity %) + Resting HR

Age

Resting Heart Rate (bpm)

Take this first thing in the morning.

The Karvonen Formula vs Standard

The standard method for calculating target heart rate simply takes a percentage of your maximum heart rate (220 - Age). This is flawed because it ignores your baseline fitness.

The Karvonen formula uses your Heart Rate Reserve (HRR). It subtracts your resting heart rate from your max, calculates the percentage of the remaining "reserve," and adds your resting rate back in. This provides a much more personalized window.

Zone Breakdown

Zone 1 (Warm Up, 50-60%): Basic activity, aids recovery.
Zone 2 (Fat Burn / Base, 60-70%): The foundation of aerobic endurance. Mitochondria density increases here. You should be able to hold a conversation.
Zone 3 (Aerobic, 70-80%): Improves cardiovascular efficiency. Conversation becomes difficult.
Zone 4 (Anaerobic, 80-90%): Increases lactate threshold. Short bursts.
Zone 5 (Max, 90-100%): Maximum effort, sustainable only for brief periods (sprints).