Find your personalized target heart rate zones for different exercise intensities using the Karvonen method, which accounts for both your age and resting heart rate. Zones range from warm-up through maximum effort.
Target heart rate is the heart rate range that produces specific training adaptations — fat burning, aerobic capacity improvement, anaerobic conditioning, or peak power. Training at the right intensity for your goal is more efficient than training too hard or too easy: too low and you don't stress the system enough to improve; too high and you burn out, risk injury, or train the wrong system.
The classic approach uses age-predicted maximum heart rate (the famous "220 minus age" rule). The Karvonen method is more individualized — it incorporates your resting heart rate to calculate heart rate reserve (HRR), then sets training zones as percentages of HRR added to your resting rate. The result accounts for the fact that two 40-year-olds with the same maximum heart rate but very different fitness levels (one with a 50 bpm resting heart rate, one with 80) should train at different absolute heart rates to produce the same training stimulus.
This calculator implements the Karvonen formula and shows your five standard training zones: Zone 1 (active recovery, 50–60% HRR), Zone 2 (aerobic base building, 60–70%), Zone 3 (aerobic endurance, 70–80%), Zone 4 (anaerobic threshold, 80–90%), and Zone 5 (maximal effort, 90–100%). Most endurance training happens in Zone 2; quality interval work happens in Zones 3–5. Use the calculator to set heart rate targets for your watch or treadmill, but remember: heart rate is one signal among many — perceived exertion, breathing rate, and pace all matter too.
Age 35, resting heart rate 72 bpm. HRmax = 220 − 35 = 185 HRR = 185 − 72 = 113 Zone 2 (aerobic base, 60–70% HRR): 140 to 151 bpm For a beginner runner, this is the right "long slow distance" zone. Should feel comfortable, conversational. Many beginners run their easy runs too hard (155+ bpm) and end up overtrained.
Age 45, resting heart rate 50 bpm (well-trained). HRmax = 220 − 45 = 175 HRR = 175 − 50 = 125 Zone 4 (anaerobic threshold, 80–90%): 150 to 163 bpm For threshold training (hard but sustainable for 30–60 minutes), this rider should aim for 150–163 bpm. Lower than the equivalent zone for a less-trained person, even at the same age — because the trained athlete's resting heart rate is so much lower.
Same person: age 50, resting HR 65 bpm. HRmax = 170 (220 − 50) HRR = 105 Zone 3 (aerobic endurance) by Karvonen (70–80% HRR): 138 to 149 bpm Zone 3 by simple %HRmax (70–80% HRmax): 119 to 136 bpm The Karvonen-calculated range is about 13–15 bpm higher. The simple %HRmax method would have this person running 30 minutes at 130 bpm thinking they're training Zone 3 aerobic endurance, but they're actually in Zone 1–2 active recovery range. The Karvonen method is more accurate when resting heart rate is meaningfully above or below typical.
Use this calculator when starting a structured training program, setting up heart rate alerts on a watch or treadmill, planning interval workouts, or trying to match training intensity to a specific goal.
Zone-based training is most useful for endurance athletes (runners, cyclists, triathletes, rowers) where heart rate is a reliable indicator of physiological stress. It's less useful for activities where heart rate is influenced by factors other than physical intensity (heavy resistance training, where heart rate spikes during sets but isn't the limiting factor; high-intensity intervals, where heart rate lags behind perceived intensity).
Pair this with the BMR/TDEE calculators (calorie planning), the calorie/calories-burned calculator (for exercise calorie tracking), and the pace/distance calculators for running (which integrate with heart rate planning).
A note on accuracy: the "220 minus age" formula is an average. Individual variation is large — your true HRmax could be ±15 bpm from the formula. The most accurate way to determine HRmax is a maximal test (running, biking, or rowing to true exhaustion), but this is intense and not for beginners. For most people, the formula is close enough to set training zones that produce the intended adaptation.
Heart rate also drifts upward in hot weather, during dehydration, after caffeine, and with stress — meaning the same physical effort produces a higher heart rate in those conditions. Some training plans intentionally use heart rate as a moderator (slower pace in heat is fine if heart rate is what's elevated) while others use rate of perceived exertion (RPE) as a backup. For serious athletes, knowing how to use both is more powerful than either alone.
A trend worth noting: "Zone 2 training" has had a resurgence in popularity, advocated by researchers like Dr. Peter Attia and Dr. Iñigo San Millán. The premise is that extended time in Zone 2 (often 3+ hours per week) builds mitochondrial density and metabolic flexibility better than higher-intensity training alone. Most well-rounded endurance programs combine substantial Zone 2 work with shorter, harder Zone 4–5 intervals.
Calculate training heart rate zones using the Karvonen method.
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Measure first thing in the morning before getting up
Max HR
190 bpm
HR Reserve
125 bpm
Fat Burn Zone
140-153
Aerobic Zone
153-165
| Detail | Value |
|---|---|
| Age | 30 years |
| Resting Heart Rate | 65 bpm |
| Max Heart Rate (220 - age) | 190 bpm |
| Heart Rate Reserve | 125 bpm |
| Zone 1 - Warm Up | 128 - 140 bpm |
| Zone 2 - Fat Burn | 140 - 153 bpm |
| Zone 3 - Aerobic | 153 - 165 bpm |
| Zone 4 - Anaerobic | 165 - 178 bpm |
| Zone 5 - Max Effort | 178 - 190 bpm |