Heart Rate Zone Calculator
Calculate your 5 heart rate training zones using the Karvonen formula.
| Zone | Name | BPM Range |
|---|---|---|
| Z1 | Recovery | 128–140 bpm |
| Z2 | Aerobic Base | 140–153 bpm |
| Z3 | Aerobic Tempo | 153–165 bpm |
| Z4 | Anaerobic Threshold | 165–178 bpm |
| Z5 | VO₂ Max | 178–190 bpm |
The 220−age formula is an estimate; individual max heart rate can vary ±10–20 bpm. For precise zones, consider a supervised field test or VO₂ max lab test.
About Heart Rate Zone Calculator
This tool calculates your five heart-rate training zones using either the Karvonen (Heart Rate Reserve) or Simple (percentage of max HR) formula. Enter your age and resting heart rate to instantly see personalized BPM targets for every zone — from easy recovery efforts in Zone 1 to all-out VO₂ max intervals in Zone 5. The Karvonen method is generally more accurate because it accounts for your fitness baseline via resting heart rate, while the simple method offers a quick estimate using only age-predicted max HR.
Built and maintained by Meet Shah · Last updated
What this tool is used for
- Deriving five training zones from a resting and a maximum heart rate.
- Checking which zone a target rate falls in.
- Setting interval targets for a session against a specific zone.
- Comparing zones derived from a measured maximum against an estimated one.
- Producing zones to load into a watch or an app.
Frequently Asked Questions
- How is maximum heart rate estimated?
- Usually 220 minus age, which is a rough population fit with a standard deviation of about 10–12 beats — so a third of people are more than ten beats from it. Tanaka's 208 − 0.7 × age fits the data better, particularly for older adults.
- What are the five zones?
- Roughly 50–60% of maximum for recovery, 60–70% for endurance, 70–80% aerobic, 80–90% threshold, 90–100% maximal. The boundaries are conventions rather than physiological cliffs, which is why different systems place them a few percent apart.
- What is the Karvonen method?
- Zones calculated from heart rate RESERVE — maximum minus resting — rather than from maximum alone. It accounts for fitness, since a trained athlete's low resting rate widens the reserve, and it typically produces higher zone boundaries than the simple percentage.
- Why does my heart rate drift up on a steady run?
- Cardiac drift — heat and dehydration reduce blood volume, so the heart compensates with more beats at the same output. On a long effort in warm conditions the rate can climb ten beats with no change in pace, which is why pace and power are better intensity guides late in a session.
- Should I test my maximum rather than estimate it?
- A lab or a supervised field test gives a genuine number and is the only way to zone accurately. It is also maximal exertion, which is not appropriate without clearance if there is any cardiovascular history — the estimate exists because the test has a real cost.
Common errors and gotchas
- Using the 220-minus-age estimate for maximum heart rate, which has a very wide error band.
- Deriving zones from a resting rate measured after coffee or on a bad night's sleep.
- Using the Karvonen formula with an estimated maximum, which compounds two approximations.
- Comparing zones across schemes, since several coaching systems define them differently.
- Using the zones through illness or heat, where the same effort produces a different rate.