Heart Rate Zone Calculator
Enter your age and resting heart rate to instantly calculate your five personalized training zones so you know exactly how hard to push during every workout.
Calculate your heart rate training zones
Enter your age and resting heart rate (measured first thing in the morning before getting out of bed).
Zone 3: 131 – 149 bpm
Aerobic / cardiovascular fitness zone, the most common training target for a 35-year-old with a 65 bpm resting heart rate.
Each colored segment is one zone, width is proportional to its bpm range. Zone 2 (the widest in most people) is the endurance workhorse; most weekly training should sit there. Zones 4–5 are the narrow red/dark segments on the right.
| Zone | Name | Range (bpm) | % of Max HR | Purpose |
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How to use this calculator
Enter your age and morning resting heart rate, then pick a method. Karvonen (recommended) uses your heart rate reserve (max HR − resting HR) to personalize zones to your fitness level. Max HR % applies fixed percentages to your estimated max HR, quicker but less individual. The result shows all five zones plus your max HR and heart rate reserve.
Tips for success
- Measure resting HR carefully. Take your pulse before rising, lie still for at least 5 minutes and count beats for a full 60 seconds for the most accurate reading.
- Karvonen gives personalized zones. A well-trained athlete with a low resting HR will have higher zone ceilings than a sedentary person of the same age.
- Zone 2 is the workhorse. Most long, easy runs and rides should stay in Zone 2 (aerobic base) to build endurance without excessive fatigue.
- Limit Zones 4 and 5. Restrict high-intensity efforts to 1–2 sessions per week to avoid overtraining and injury.
- Use a chest strap for accuracy. Wrist-based optical sensors are far less accurate than chest straps during high-intensity efforts.
Practical note
The 220 − age formula for maximum heart rate is a population average with a standard deviation of ±10–12 bpm. Your true max HR can vary considerably. For precision, consider a supervised max HR test or use actual field-test data once you have it. These zones are a starting point, not a medical prescription.
Understanding the five training zones
- Zone 1, Active Recovery (50–60% max HR): Very easy effort. Used for warm-ups, cool-downs, and recovery days. Promotes blood flow without taxing the body.
- Zone 2, Fat Burning / Aerobic Base (60–70% max HR): Comfortable conversational pace. Burns a higher proportion of fat as fuel. Builds mitochondrial density and long-term endurance. The foundation of any training plan.
- Zone 3, Aerobic / Cardiovascular (70–80% max HR): Moderate effort where breathing becomes noticeable. Improves cardiovascular efficiency and lactate clearance. Great for tempo runs and steady rides.
- Zone 4, Lactate Threshold / High Intensity (80–90% max HR): Hard effort, you can speak only a few words at a time. Raises your lactate threshold, which is the single biggest predictor of endurance performance. Use sparingly.
- Zone 5, VO2 Max / Anaerobic (90–100% max HR): All-out effort sustainable for only 30–120 seconds. Builds peak power and speed. Reserved for short intervals and should make up a small fraction of weekly training volume.
Common mistakes when training by heart rate
- Training too hard, too often. Most recreational athletes spend far too much time in Zone 3/4 and not enough in Zone 2, leading to chronic fatigue without proportional gains.
- Using an inaccurate resting HR. Taking a single casual measurement while stressed or after caffeine will skew your Karvonen zones; average three morning readings for best results.
- Ignoring environmental factors. Heat, humidity, altitude, illness, and poor sleep all raise heart rate independently of exertion; be prepared to scale back targets on tough days.
- Never recalculating. As fitness improves your resting HR may drop, which shifts your zones; recalculate every 4–8 weeks during a training block.
- Conflating estimated max HR with actual max HR. If you have had a true max HR test, use that number instead of the 220 − age estimate for far more accurate zones.
FAQ
What is the best formula for maximum heart rate?
The classic formula 220 − age is widely used and built into this calculator. More refined alternatives include 208 − (0.7 × age) (Tanaka formula), which tends to be more accurate for older adults. If you have performed a verified max HR test, such as a supervised graded exercise test or a genuine all-out field effort, enter that value directly into a Karvonen formula manually for the most precise zones. This calculator uses 220 − age as a practical default suitable for most users.
What is a normal resting heart rate?
For healthy adults, a resting heart rate between 60 and 100 bpm is considered normal. Well-trained endurance athletes commonly see resting heart rates in the 40–55 bpm range. Values below 40 bpm should be discussed with a physician unless you are an elite athlete. A resting HR consistently above 90 bpm may warrant a medical check-up. Measure yours on multiple mornings before getting out of bed for the most reliable number.
How often should I train in each zone?
A common evidence-based guideline is the 80/20 rule: roughly 80% of training time in Zones 1–2 (easy aerobic) and about 20% in Zones 3–5 (moderate to high intensity). This distribution is used by elite endurance athletes worldwide and has strong support in exercise science research. Beginners should lean even more toward Zone 1–2 until a solid aerobic base is established, typically 4–8 weeks of consistent easy effort.
Why does my heart rate spike above Zone 5 during sprints?
Heart rate is a lagging indicator of effort, it takes 15–60 seconds to catch up to a sudden surge in exercise intensity. During very short, maximal sprints (under 15–20 seconds) your heart rate may not have time to reach its true peak before the effort ends. For interval training at very high intensities, power output (on a bike) or pace (running) may be a better in-the-moment guide, with heart rate used as a general post-interval check.
Can I use these zones for activities other than running?
Yes. Heart rate zones apply to any aerobic activity, cycling, rowing, swimming, hiking, elliptical, and even heavy manual labor. However, be aware that upper-body-dominant activities like rowing or arm cycling tend to produce lower maximum heart rates than running by 5–10 bpm, so running-derived zones may feel harder than expected in those activities. Swimming max HR is typically 10–13 bpm lower than running due to the horizontal position and cooler water.