Target Heart Rate Zone Calculator
Calculate your 5 training heart rate zones using the Karvonen method, from your age and resting heart rate.
Estimated max heart rate
190 bpm
Heart rate reserve
125 bpm
| Zone | Target range | Best for |
|---|---|---|
| Zone 1 — Very light | 128–140 bpm | Warm-up, recovery |
| Zone 2 — Light (fat burn) | 140–153 bpm | Base endurance, fat metabolism |
| Zone 3 — Moderate (aerobic) | 153–165 bpm | Cardiovascular fitness |
| Zone 4 — Hard (anaerobic) | 165–178 bpm | Performance, speed |
| Zone 5 — Maximum | 178–190 bpm | Short, high-intensity efforts |
Uses the Karvonen method (heart rate reserve × intensity % + resting heart rate), which accounts for your fitness level via resting heart rate — more individualized than the simpler "max HR × %" method.
About this tool
How to use it
- Enter your age and your resting heart rate — measured first thing in the morning before getting up is most accurate, or use your fitness tracker's reported resting heart rate.
- Read the 5 target zones together — each is a target bpm range for a different training purpose, from easy recovery to maximum effort.
- Pick the zone that matches what you're training for on a given day, and check your heart rate against it during exercise.
- Click Calculate, or just keep typing — everything updates live.
Why it matters
Training 'by feel' alone makes it easy to always default to a similar moderate effort, missing out on both easy recovery days and genuinely hard efforts — both of which contribute differently to fitness. Heart rate zones give an objective number to train to, rather than a subjective sense of effort that changes with tiredness, weather, or motivation.
When to use it
Planning a structured cardio or endurance training week that includes both easy and hard sessions. Making sure a 'recovery run' actually stays easy, or that an interval session actually reaches a hard enough effort. Understanding what a fitness tracker's heart rate zone feature is actually basing its zones on.
Good to know
Uses the Karvonen method: target HR = (max HR − resting HR) × intensity% + resting HR. This is more individualized than the simpler 'max HR × intensity%' method because it accounts for your actual resting heart rate (a rough proxy for cardiovascular fitness), not just your age. Max heart rate itself is estimated as 220 − age, a widely used but approximate formula — actual maximum heart rate varies meaningfully between individuals of the same age (by ±10-15 bpm is not unusual), so these zones are a well-reasoned estimate, not a lab-measured value.
Common questions
Why does this need my resting heart rate, not just my age?
The Karvonen method uses 'heart rate reserve' (max HR minus resting HR) instead of just max HR, which makes the zones reflect your actual cardiovascular fitness rather than age alone — two 40-year-olds with very different fitness levels typically have different resting heart rates, and this method accounts for that difference.
How do I measure my resting heart rate accurately?
The most accurate reading is taken first thing in the morning, before getting out of bed, using a heart rate monitor or by counting your pulse for 60 seconds. A fitness tracker's reported average or lowest overnight heart rate is also a reasonable substitute.
Is 220 minus age an accurate way to find my max heart rate?
It's a widely used population-average estimate, not a precise individual measurement — actual maximum heart rate can vary by roughly ±10-15 bpm from this formula's prediction for people of the same age. A supervised maximal exercise test is the only way to get a truly measured value.
Which zone should I train in most?
This depends entirely on your training goals — most endurance training plans recommend spending the majority of training time in Zones 2-3 (light to moderate) with occasional sessions in Zones 4-5 for higher-intensity work, but the right mix varies by sport, experience level, and specific goals. This tool calculates the zones; it doesn't prescribe a training plan.
Is this medical advice?
No — this is a standard fitness training calculation, not a medical assessment. Anyone with a heart condition, or starting a new exercise program after a long period of inactivity, should consult a doctor before using heart rate zones to guide exercise intensity.