Heart Rate Zone Calculator – Find Your Target Training Zones
The Heart Rate Zone Calculator helps you determine your personalized cardio training zones based on your age, resting heart rate, and biological sex. Knowing your heart rate zones allows you to train smarter — whether your goal is burning fat, building endurance, or pushing your peak performance. Enter your details below to instantly see your five training zones in beats per minute.
Enter your current age in years.
Measure your resting heart rate in the morning before getting out of bed.
Karvonen uses your resting heart rate for more personalized zones. Max HR % is simpler.
Sex is used to refine the maximum heart rate estimate.
Your results will appear here
How to Use This Calculator
1. Enter your current age in years. 2. Measure your resting heart rate (ideally in the morning before rising) and enter it in the Resting Heart Rate field. 3. Choose a calculation method — Karvonen is recommended for most people as it accounts for your fitness level via resting heart rate, while Max HR % is a simpler alternative. 4. Select your biological sex to refine the maximum heart rate estimate. 5. Click Calculate to instantly see your estimated maximum heart rate, heart rate reserve, and all five training zones with their bpm ranges.
Understanding Heart Rate Training Zones
Heart rate zones are ranges of beats per minute (bpm) that correspond to different exercise intensities. Training in specific zones produces different physiological adaptations — from fat burning to cardiovascular endurance to anaerobic power. Most exercise scientists define five zones, each representing a percentage of your maximum heart rate.
How Maximum Heart Rate Is Estimated
Your maximum heart rate (MHR) is the highest your heart can beat per minute during all-out effort. Rather than requiring a grueling max-effort test, we estimate it using research-backed formulas:
- Males: MHR = 208 − (0.7 × age) — from Tanaka et al. (2001)
- Females: MHR = 206 − (0.88 × age) — from Gulati et al. (2010)
These formulas are more accurate than the classic "220 minus age" approach, especially for older adults.
The Karvonen Method (Heart Rate Reserve)
The Karvonen method, also called the Heart Rate Reserve (HRR) method, accounts for your current fitness level by incorporating your resting heart rate:
- HRR = Maximum Heart Rate − Resting Heart Rate
- Target HR = (HRR × Intensity %) + Resting Heart Rate
Because a fitter person has a lower resting heart rate, this method produces higher training zone targets for fit individuals and lower targets for beginners — a more personalized prescription.
The Five Training Zones Explained
Zone 1 – Warm-Up (50–60%)
Very light activity. Ideal for warm-ups, cool-downs, and active recovery days. Improves overall health and helps muscles recover between hard sessions.
Zone 2 – Fat Burn (60–70%)
Light to moderate effort. The body primarily uses fat as fuel in this zone. Great for long, easy runs, cycling, or any sustained low-intensity cardio. Builds aerobic base and improves mitochondrial density over time.
Zone 3 – Aerobic (70–80%)
Moderate effort — you can still hold a conversation but it's challenging. Improves cardiovascular efficiency, increases stroke volume, and enhances lactate clearance. This is the sweet spot for general fitness improvement.
Zone 4 – Anaerobic Threshold (80–90%)
Hard effort. The body transitions from aerobic to anaerobic metabolism, and lactate begins to accumulate. Training here raises your lactate threshold, allowing you to sustain higher intensities longer. Used in tempo runs and interval training.
Zone 5 – Maximum (90–100%)
All-out effort — only sustainable for short bursts (seconds to a couple of minutes). Develops maximum speed, power, and VO₂ max. Reserved for sprint intervals and competitive athletes.
How to Use Your Zones
- Wear a heart rate monitor during workouts to stay in target zones.
- Beginners should spend most training time in Zones 1–2.
- Intermediate athletes benefit from a 80/20 split: 80% easy (Zones 1–2), 20% hard (Zones 4–5).
- Zone 3 is often called the "grey zone" — not easy enough for recovery, not hard enough for maximum adaptation — use it sparingly.