Heart Rate Zone Calculator
Calculate your 5 heart rate training zones using Karvonen or percentage method. Optimise workouts for fat burn, endurance, and VO2 max.
Enter your age (and optionally resting HR) to calculate personalised heart rate training zones.
Why Training by Heart Rate Beats Training by Feel
"Go hard" isn't a training plan. Your body responds differently to different intensities, and the only way to ensure you're in the right zone is to measure it. A heart rate monitor turns guesswork into precision.
Each of the 5 heart rate zones triggers specific physiological adaptations — from fat burning and endurance building in the lower zones to lactate threshold and VO2 max improvements in the higher zones. Training in the wrong zone means you're working hard but not getting the results you want.
The 5 Heart Rate Zones Explained
| Zone | % Max HR | Feels Like | What It Trains | How Long |
|---|---|---|---|---|
| Zone 1: Recovery | 50–60% | Very easy, can chat freely | Active recovery, warm-up | 30–60 min |
| Zone 2: Aerobic Base | 60–70% | Comfortable, can hold conversation | Fat burning, endurance foundation | 45–120 min |
| Zone 3: Tempo | 70–80% | Moderate, short sentences only | Aerobic capacity, efficiency | 20–40 min |
| Zone 4: Threshold | 80–90% | Hard, can barely talk | Lactate threshold, race speed | 10–20 min intervals |
| Zone 5: VO2 Max | 90–100% | Maximum effort, can't talk | Max oxygen uptake, sprint power | 30 sec–3 min intervals |
What this means for you: Most recreational athletes spend too much time in Zone 3 — the "no man's land" that's too hard for recovery but too easy for real improvement. Elite athletes spend 80% of their training in Zones 1–2 and 20% in Zones 4–5. This "polarised training" approach produces the best long-term results.
Karvonen vs Percentage Method: Which Is More Accurate?
The percentage method calculates zones as simple percentages of your max heart rate. It's easy but ignores your fitness level.
The Karvonen method uses your heart rate reserve (max HR minus resting HR), which accounts for individual fitness. A fit person with a resting HR of 50 bpm gets different zones than an unfit person with a resting HR of 80 bpm — even if they're the same age.
Use Karvonen if you know your resting heart rate (measure it first thing in the morning). Use the percentage method only if you don't have resting HR data. The Karvonen zones are more personalised and more accurate, especially for Zone 2 training.
How to Find Your True Max Heart Rate
The formula 220 minus age is popular but inaccurate — it can be off by 10–20 bpm. The Tanaka formula (208 − 0.7 x age) is better but still an estimate. The only reliable way to find your true max HR is a field test:
- Warm up for 10 minutes at an easy pace
- Find a hill that takes 2–3 minutes to climb (or use a treadmill incline)
- Run up at a hard effort — not quite a sprint, but close to maximum
- Jog back down and repeat 3 times, going harder each time
- On the third repeat, sprint the last 30 seconds all-out
- The highest heart rate recorded during the test is your max HR
Warning: Only attempt this if you're healthy and have been exercising regularly. If you have any heart conditions, get a supervised stress test from a cardiologist instead.
Resting Heart Rate: What It Tells You
| Resting HR (bpm) | Fitness Level | Typical For |
|---|---|---|
| Below 50 | Elite | Endurance athletes, professional cyclists |
| 50-59 | Excellent | Regular runners, swimmers, serious gym-goers |
| 60-69 | Good | Active adults who exercise 3-4 times per week |
| 70-79 | Average | Moderately active adults |
| 80-89 | Below average | Sedentary adults, may indicate poor fitness |
| 90+ | See a doctor | May indicate stress, dehydration, or underlying condition |
Measure your resting heart rate first thing in the morning, before getting out of bed. Track it weekly — a gradually declining RHR over months is one of the best signs that your fitness is improving. A sudden spike of 10+ bpm can indicate illness, overtraining, or stress.
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How to use this tool
Enter your age
Enter your resting heart rate (optional, enables Karvonen method)
Choose between Karvonen or percentage method
Common uses
- Setting heart rate targets for cardio workouts
- Finding the right intensity for fat-burning exercise
- Training for a marathon, triathlon, or cycling event
- Monitoring intensity during HIIT sessions
- Building an aerobic base with Zone 2 training
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