Target Heart Rate
Find exercise heart rate zones using Karvonen method.
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How This Target Heart Rate Works
This calculator uses established scientific formulas validated in peer-reviewed literature. All calculations run locally in your browser — no data is sent to any server.
Heart Rate Training Zones
| Zone | % Max HR | Benefit | RPE |
|---|---|---|---|
| Zone 1 (Warm Up) | 50 – 60% | Recovery, warm-up | Light |
| Zone 2 (Fat Burn) | 60 – 70% | Fat oxidation, endurance base | Easy |
| Zone 3 (Aerobic) | 70 – 80% | Cardiovascular fitness | Moderate |
| Zone 4 (Threshold) | 80 – 90% | Lactate threshold, speed | Hard |
| Zone 5 (VO2 Max) | 90 – 100% | Max performance, intervals | All-out |
The Karvonen Method vs 220-Minus-Age
The basic "220 minus age" formula only estimates max heart rate. The Karvonen method (used here) is more personalized because it factors in your resting heart rate, which reflects your fitness level. A fit person with a resting HR of 50 will get different zones than an untrained person with a resting HR of 75 — even at the same age.
Use Zone 2 (fat burn) for 80% of your training and Zone 4–5 for 20% of sessions. Track calorie burn with the Calories Burned Calculator. For running, pair with the Pace Calculator. Support cardiovascular training with adequate calories and hydration.
Why Resting Heart Rate Matters
Your resting heart rate (RHR) is one of the most accessible indicators of cardiovascular fitness. Elite endurance athletes often have RHR below 50 bpm; sedentary adults average 70-80 bpm. As you become fitter, your heart becomes more efficient — pumping more blood per beat — so it needs fewer beats to supply your body at rest. Tracking RHR over time is a simple way to monitor fitness improvements.
The Karvonen method used in this calculator leverages RHR to personalize your training zones. A 30-year-old with a resting HR of 50 (fit) gets very different zone boundaries than a 30-year-old with a resting HR of 80 (sedentary), even though both have the same predicted max HR. This personalization makes Karvonen significantly more accurate than the basic "percentage of max HR" approach.
Training Zone Application
The 80/20 rule is the most evidence-backed approach to zone distribution: spend 80% of your training time in Zones 1-2 (easy, conversational) and 20% in Zones 4-5 (hard, intervals). This pattern is used by elite athletes across running, cycling, rowing, and swimming. Research from Stephen Seiler at the University of Agder found that this "polarized" distribution produces superior results to "threshold" training (spending most time in Zone 3).
Pair heart rate training with the Pace Calculator for running, the Calories Burned Calculator for energy tracking, and adequate nutrition to fuel your training load.
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