Estimate your maximum heart rate, set your resting heart rate, and get personalised training zones based on your goal.
| Zone | % of HRR | % of max HR | Heart rate range | Training benefit |
|---|
| Quantity | Value | Formula | Notes |
|---|
| Aim | Primary zones | Session style | Your ratio |
|---|
| Metric | Value | Notes |
|---|
-
Select a citation style above. Click the citation text to select it all, then copy.
ADVERTISEMENT
Founder & CEO, Toolraxy
Faiq Ur Rahman is a web designer, digital product developer, and founder of Toolraxy, a growing platform of web-based calculators and utility tools. He specializes in building structured, user-friendly tools focused on health, finance, productivity, and everyday problem-solving.
User Ratings:
ADVERTISEMENT
ADVERTISEMENT
A heart rate zone calculator turns a single max HR number into a training plan. But the method you use to build those zones matters. A simple percentage of max HR ignores resting heart rate, which varies enormously between people of the same age. The Karvonen method, Heart Rate Reserve fixes that by using the range between your resting and maximum heart rate as the denominator.
This tool estimates your max HR from one of three formulas, lets you enter a lab-measured value if you have one, and asks whether you know your resting HR. If you don’t, it estimates one from your age. Then it builds five training zones and highlights the ones that match your goal: weight loss, endurance, or strength and speed.
Cyclists use these zones to pace intervals. Runners use them to keep easy days easy. Beginners use them to figure out what “moderate” actually means in beats per minute.
Four inputs drive the result: age, max HR formula, resting HR, and training aim. Age feeds the max HR estimate. Resting HR sets the low end of your reserve. The aim selects which zones get highlighted as your primary training targets.
Choose a max HR formula. Tanaka (default), Fox, Gulati, or Custom. Pick Custom if you have a lab-measured value.
Enter your age. Used by the formula to estimate max HR. Default is 30.
Confirm your max HR. If you picked a formula, the field fills automatically. If you picked Custom, type your measured value.
Answer whether you know your resting HR. Select “No” to use an age-based estimate, or “Yes” to enter your own.
Enter your resting HR if you have it. Measure first thing in the morning, before getting out of bed. Default is 60 bpm.
Select your training aim. Weight loss, endurance, or strength/speed. This highlights the primary zones for that goal.
Read your recommended zone. The hero number shows which zone to train in most of the time, with the bpm range.
Scan the zone table. All five zones are shown with their % of HRR, % of max HR, and bpm range. Your primary zones are highlighted.
The calculator uses the Karvonen formula, also called the Heart Rate Reserve method. It starts by finding your heart rate reserve (max HR minus resting HR), then applies an intensity percentage to that reserve, and adds your resting heart rate back.
Formula (Karvonen): Target HR = (HRR × Intensity%) + RHR
Formula (Heart Rate Reserve): HRR = Max HR − Resting HR
Formula (Tanaka max HR): Max HR = 208 − (0.7 × Age)
Formula (Fox max HR): Max HR = 220 − Age
Formula (Gulati max HR for women): Max HR = 206 − (0.88 × Age)
Your zones come from three inputs. Anything that changes those inputs shifts the bpm ranges. Some factors are biological, some are measurement artefacts, and some are medication effects.
Resting heart rate. A lower resting HR widens your HRR, which pushes every zone boundary up. Endurance training lowers resting HR over time, so your zones shift as you get fitter.
Max heart rate formula. Tanaka, Fox, and Gulati produce different max HR estimates for the same age. The choice of formula shifts all five zones by 5–10 bpm.
Age. Max HR declines with age, which lowers your HRR and shifts zones down. A 50-year-old has lower zone targets than a 30-year-old at the same resting HR.
Fitness level. Trained individuals have lower resting HRs, which widens their HRR. But they also reach higher percentages of their HRR at threshold, so their effective training zones may be higher than the Karvonen model predicts.
Medications. Beta-blockers lower both resting and max heart rate. The Karvonen formula may produce zones that are too high for patients on these drugs.
Caffeine and stress. Both raise resting heart rate. A morning coffee before measuring resting HR can add 5–10 bpm, narrowing your HRR and shifting zones down.
Heat and dehydration. Both increase heart rate at any given intensity. The zones from the calculator assume normal conditions.
Altitude. At altitude, heart rate is higher for the same oxygen consumption. The calculator doesn’t adjust for this.
Sport. Running produces a higher heart rate at the same perceived effort than cycling because more muscle mass is involved. The calculator’s zones apply across sports but may need adjustment.
A 38-year-old woman has a resting heart rate of 52 bpm and wants to train for endurance. She selects the Tanaka formula for max HR and enters her resting HR.
Step 1: Estimate max HR using Tanaka. 208 − (0.7 × 38) = 208 − 26.6 = 181 bpm.
Step 2: Calculate heart rate reserve. 181 − 52 = 129 bpm.
Step 3: Calculate Zone 2 (60–70% HRR). (129 × 0.60) + 52 = 129.4 bpm. (129 × 0.70) + 52 = 142.3 bpm. So Zone 2 is 129–142 bpm.
Step 4: Calculate Zone 3 (70–80% HRR). (129 × 0.70) + 52 = 142.3 bpm. (129 × 0.80) + 52 = 155.2 bpm. So Zone 3 is 142–155 bpm.
Step 5: Calculate Zone 4 (80–90% HRR). (129 × 0.80) + 52 = 155.2 bpm. (129 × 0.90) + 52 = 168.1 bpm. So Zone 4 is 155–168 bpm.
The calculator recommends Zones 2–4 for endurance. Her target range for most training is 129–168 bpm, with the middle zone (Zone 3) as the focal point at 142–155 bpm.
A man the same age with a resting HR of 70 would have an HRR of 111 bpm. His Zone 3 would be (111 × 0.70) + 70 = 147.7 to (111 × 0.80) + 70 = 158.8, or 148–159 bpm. The woman’s lower resting HR gives her a lower absolute Zone 3 target despite having a higher HRR.
The five-zone model is the standard in exercise physiology. Each zone corresponds to a physiological intensity and a primary training adaptation.
Zone 1 (50–60% of HRR) is recovery. It’s the intensity you use for warm-ups, cool-downs, and easy days between hard sessions. The physiological goal is blood flow without stress. It feels easy. You can hold a conversation without effort.
Zone 2 (60–70% of HRR) is the aerobic base. This is where fat oxidation is highest, mitochondrial density increases, and the heart’s stroke volume improves. It’s the foundation of endurance training. Most recreational athletes spend too little time here and too much in Zone 3. Zone 2 feels like you’re not working hard enough, which is exactly the point.
Zone 3 (70–80% of HRR) is tempo. It’s comfortably hard — you can talk, but not in long sentences. It improves aerobic power and your ability to sustain faster paces. It’s the middle ground between easy base work and hard threshold intervals.
Zone 4 (80–90% of HRR) is threshold. This is where lactate accumulates faster than it clears, and where you can only sustain effort for 20–60 minutes. Threshold training pushes that limit higher. It’s the most important zone for race performance in events lasting 30 minutes to two hours.
Zone 5 (90–100% of HRR) is VO2 max. It’s maximal effort, sustainable for seconds to a few minutes. It develops your ceiling. It’s also the zone that requires the most recovery.
Zone 1 (50–60% HRR) is recovery. Zone 2 (60–70%) is aerobic base. Zone 3 (70–80%) is tempo. Zone 4 (80–90%) is threshold. Zone 5 (90–100%) is VO2 max.
Use the Karvonen formula: Target HR = (HRR × intensity) + resting HR. Heart rate reserve is max HR minus resting HR. The calculator does this for all five zones automatically.
The Karvonen formula calculates a target heart rate from heart rate reserve: Target HR = (Max HR − Resting HR) × Intensity% + Resting HR. It’s the standard method for exercise prescription in sports science and cardiac rehabilitation.
Zone 2 (60–70% of HRR) burns the highest percentage of calories from fat. Higher zones burn more total calories but a lower percentage from fat. For weight loss, total energy expenditure matters more than the fat-burning percentage.
Zone 2 is 60–70% of your heart rate reserve. It feels like a light to moderate effort where you can hold a conversation. It’s the foundation of aerobic base training.
Zones 2 and 3. Zone 2 builds your aerobic base with long, steady sessions. Zone 3 adds tempo work to improve your aerobic power. Zone 4 is used for threshold intervals.
Zone 2 for long duration, but total calorie burn matters more than the zone. A mix of Zone 2 steady-state work and higher-intensity intervals (Zones 3–4) produces the best results for most people.
For most adults, 60–80 bpm. Well-trained athletes often sit at 40–60 bpm. A lower resting HR generally indicates better cardiovascular fitness.
The Tanaka formula is: Max HR = 208 − 0.7 × age. It’s more accurate than the older 220 − age formula, especially for people over 40.
The Gulati formula is: Max HR = 206 − 0.88 × age. It was derived from over 5,000 women and is more accurate for women than the Fox or Tanaka formulas.
It’s a rough estimate. The Fox formula (220 − age) has a standard error of about 12 bpm, which means a predicted max HR of 180 could be 168 or 192 in reality. It tends to overestimate in women and underestimate in men.
Use the Tanaka formula: 208 − 0.7 × age. If you’re a woman, use the Gulati formula: 206 − 0.88 × age. Both are more accurate than 220 − age.
ADVERTISEMENT
ADVERTISEMENT
