❤️Heart Rate Zones Calculator
Calculate your 5 personalized heart rate training zones using the Karvonen formula to optimize your workouts for fat burn, aerobic fitness, and peak performance.
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Max Heart Rate (bpm)
185
Your maximum heart rate is 185 bpm. Your fat burn zone is 137–149 bpm and your aerobic zone is 149–161 bpm.
Heart Rate Zones (bpm)
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Heart Rate Zones Calculator: Target Heart Rate and Training Zones by Age
A heart rate zones calculator takes your age and resting heart rate and produces personalized training zones in beats per minute (BPM). Knowing your target heart rate zones transforms vague workouts into structured, goal-directed sessions. Whether you want to burn fat, build cardiovascular endurance, or push your peak performance, training in the correct heart rate zone is the difference between a workout that works and one that just leaves you tired. This calculator uses the Karvonen formula, the most personalized and widely recommended method for calculating heart rate training zones.
Max Heart Rate Calculator by Age: The 220 Minus Age Formula
The starting point for any heart rate zones calculator is your maximum heart rate (MHR). The most commonly used estimate is 220 minus your age. A 35-year-old would have an estimated max HR of 185 BPM. A 50-year-old would be 170 BPM.
This formula is a population average with a standard deviation of about 10 to 12 BPM, meaning your true maximum heart rate could be 10 to 20 BPM higher or lower than the formula predicts. For a more accurate max HR, you can use your highest recorded heart rate from an all-out effort during a timed run or cycling sprint, or undergo a graded exercise test supervised by a fitness professional. If you know your actual max HR, enter it in the calculator to get more precise zones.
Heart Rate Zone Calculator for Fat Burning: Zone 2 Explained
The fat burning zone, also called Zone 2, covers 60 to 70% of your heart rate reserve (HRR). At this moderate intensity, your body relies more heavily on fat as a fuel source compared to carbohydrates, which is why it is often targeted for weight management. You should be able to hold a full conversation at this effort level.
Zone 2 training has gained significant attention from exercise physiologists and longevity researchers. Long Zone 2 sessions build mitochondrial density, improve fat oxidation efficiency, and form the aerobic base that supports all higher-intensity exercise. Elite endurance athletes typically spend 70 to 80% of their total training volume in this zone, a method called polarized training or base building.
Aerobic vs. Anaerobic Heart Rate Zones
Understanding the difference between aerobic and anaerobic zones is key to structuring effective training:
- Zone 1 - Recovery (50 to 60% HRR): Very easy effort. Promotes active recovery between hard sessions, warms up the body, and builds base aerobic fitness. Sustainable indefinitely for most people.
- Zone 2 - Fat Burn (60 to 70% HRR): Conversational pace. Primarily aerobic, fat-fueled. The cornerstone of endurance training and metabolic health.
- Zone 3 - Aerobic (70 to 80% HRR): Comfortably hard. Uses a mix of fat and carbohydrates. Sustainable for 30 to 60 minutes in trained individuals. A useful fitness zone, though some coaches caution against overusing it at the expense of Zone 1-2 or Zone 4-5 work.
- Zone 4 - Anaerobic Threshold (80 to 90% HRR): Challenging effort at or near the lactate threshold. Training here raises the intensity at which lactate begins to accumulate, the single strongest predictor of endurance performance. Sustainable for 15 to 30 minutes. Tempo runs and threshold intervals target this zone.
- Zone 5 - Maximum Effort (90 to 100% HRR): All-out sprinting. Builds peak power, speed, and VO2 max. Sustainable for only seconds to a couple of minutes. Requires significant recovery time between sessions.
Heart Rate Zones for Cardio Exercise: The Karvonen Formula Advantage
Most basic heart rate zone charts use simple percentages of maximum heart rate, for example, "Zone 2 is 60 to 70% of max HR." The Karvonen formula is more accurate because it accounts for your resting heart rate, which reflects your current cardiovascular fitness level.
The formula: Target HR = (Heart Rate Reserve x Intensity %) + Resting HR, where Heart Rate Reserve = Max HR minus Resting HR.
A fit 35-year-old with a resting HR of 45 BPM and a max HR of 185 BPM has an HRR of 140 BPM. Their Zone 2 ceiling is (140 x 0.70) + 45 = 143 BPM. A less fit person of the same age with a resting HR of 75 BPM has an HRR of 110 BPM. Their Zone 2 ceiling is (110 x 0.70) + 75 = 152 BPM. Simple percentage methods would give both the same number (130 BPM), which underestimates the fit person's actual capacity and overestimates their easier zones.
How to Measure Your Resting Heart Rate Accurately
Your resting heart rate is best measured first thing in the morning before you get out of bed. Lie still for a few minutes, then count your pulse for a full 60 seconds. Normal resting heart rates for adults range from 60 to 80 BPM. Trained endurance athletes typically fall in the 40 to 55 BPM range. A wearable heart rate monitor or fitness tracker worn during sleep can also provide an accurate resting heart rate reading.
Frequently Asked Questions
How do I calculate my maximum heart rate?
The most common method is the formula 220 minus your age. A 40-year-old would have an estimated maximum heart rate of 180 BPM. This is a population average and can be off by 10 to 20 BPM for any individual. For a more accurate reading, use your highest heart rate recorded during an all-out effort like a hard sprint or hill climb, or undergo a graded exercise test with a fitness professional. Entering your actual max HR in the calculator produces more precise training zones.
What heart rate zone burns the most fat?
Zone 2 (the fat burning zone, 60 to 70% of heart rate reserve) burns the highest proportion of fat as a fuel source. At this intensity, fat provides a greater percentage of the energy used compared to carbohydrates. However, higher-intensity zones burn more total calories per session, which also contributes to fat loss. For overall body composition, a combination of longer Zone 2 sessions and shorter Zone 4 to 5 interval sessions tends to produce the best results.
What is the difference between aerobic and anaerobic zones?
Aerobic zones (Zones 1 through 3) are intensities where your body can meet energy demand using oxygen, burning primarily fat and some carbohydrates. You can sustain these efforts for extended periods. Anaerobic zones (Zones 4 and 5) are high intensities where energy demand exceeds what the aerobic system can supply alone. Your body shifts toward burning carbohydrates rapidly and produces lactate as a byproduct. These efforts are unsustainable for long periods and require more recovery time.
How do I use heart rate zones to improve fitness?
The most effective approach for most people is to structure training across zones deliberately. Spend the majority of cardio time (roughly 70 to 80%) in Zone 1 and Zone 2 to build your aerobic base. Add one to two sessions per week in Zone 4 to 5 to develop speed, power, and VO2 max. This polarized approach has been shown in research to produce better fitness adaptations than spending most time at moderate Zone 3 intensity. Use a heart rate monitor during workouts to ensure you are actually hitting your target zones.