HIFreeTools
ENES

Heart Rate Zone Calculator

Find your personalized heart rate training zones using the science-backed Karvonen formula, which accounts for both your age and resting heart rate for more accurate targets.

Measure resting HR first thing in the morning before getting out of bed.

Enter your age and resting heart rate to see your 5 training zones.

Formula: Karvonen method — Target HR = (HRR × Intensity) + Resting HR

Max HR = 220 − Age  |  HRR = Max HR − Resting HR

Results are estimates. Consult a physician before starting a new exercise programme, especially if you take heart-rate–affecting medications.

Quick answer

Heart rate training zones are calculated using the Karvonen formula: Target HR = (Heart Rate Reserve × Zone%) + Resting HR, where Heart Rate Reserve = Max HR − Resting HR and Max HR = 220 − Age. The 5 standard zones range from Zone 1 (50–60% HRR, active recovery) to Zone 5 (90–100% HRR, maximum effort). For a 30-year-old with a resting HR of 65 bpm, Zone 2 (aerobic base) runs from 140 to 153 bpm. Training across all five zones improves cardiovascular fitness, fat oxidation, lactate threshold, and peak power output.

Formula & method

Max HR = 220 − Age
  • Max HR — Maximum heart rate in beats per minute (bpm)
  • Age — Age in years

Age-predicted maximum heart rate (Tanaka formula variant: 208 − 0.7 × Age is more accurate for older adults but 220 − Age remains the standard default).

HRR = Max HR − Resting HR
  • HRR — Heart Rate Reserve in bpm
  • Resting HR — Resting heart rate in bpm, measured first thing in the morning

Heart Rate Reserve is the difference between your maximum and resting heart rates. A larger HRR indicates better cardiovascular fitness.

Target HR = (HRR × Intensity%) + Resting HR
  • Target HR — Target heart rate in bpm for a given zone
  • HRR — Heart Rate Reserve in bpm
  • Intensity% — Zone lower or upper boundary as a decimal (e.g., 0.60 for 60%)
  • Resting HR — Resting heart rate in bpm

Karvonen formula for calculating the target heart rate at a given training intensity percentage. More personalised than simple percentage-of-max-HR methods.

Examples

Example 1: 30-year-old recreational runner, resting HR 65 bpm
Input
Age: 30, Resting HR: 65 bpm
Result
Max HR: 190 bpm | HRR: 125 bpm | Zone 1: 128–140 bpm | Zone 2: 140–153 bpm | Zone 3: 153–165 bpm | Zone 4: 165–178 bpm | Zone 5: 178–190 bpm
Why
Max HR = 220 − 30 = 190. HRR = 190 − 65 = 125. Zone 2 lower = (125 × 0.60) + 65 = 75 + 65 = 140. Zone 2 upper = (125 × 0.70) + 65 = 87.5 + 65 = 152.5 ≈ 153.
Example 2: 45-year-old cyclist, resting HR 70 bpm
Input
Age: 45, Resting HR: 70 bpm
Result
Max HR: 175 bpm | HRR: 105 bpm | Zone 1: 123–133 bpm | Zone 2: 133–144 bpm | Zone 3: 144–154 bpm | Zone 4: 154–165 bpm | Zone 5: 165–175 bpm
Why
Max HR = 220 − 45 = 175. HRR = 175 − 70 = 105. Zone 3 lower = (105 × 0.70) + 70 = 73.5 + 70 = 143.5 ≈ 144. Zone 4 upper = (105 × 0.90) + 70 = 94.5 + 70 = 164.5 ≈ 165.
Example 3: 25-year-old elite athlete, resting HR 55 bpm
Input
Age: 25, Resting HR: 55 bpm
Result
Max HR: 195 bpm | HRR: 140 bpm | Zone 1: 125–139 bpm | Zone 2: 139–153 bpm | Zone 3: 153–167 bpm | Zone 4: 167–181 bpm | Zone 5: 181–195 bpm
Why
Max HR = 220 − 25 = 195. HRR = 195 − 55 = 140. Zone 4 lower = (140 × 0.80) + 55 = 112 + 55 = 167. Zone 5 lower = (140 × 0.90) + 55 = 126 + 55 = 181.
Example 4: 55-year-old fitness walker, resting HR 75 bpm
Input
Age: 55, Resting HR: 75 bpm
Result
Max HR: 165 bpm | HRR: 90 bpm | Zone 1: 120–129 bpm | Zone 2: 129–138 bpm | Zone 3: 138–147 bpm | Zone 4: 147–156 bpm | Zone 5: 156–165 bpm
Why
Max HR = 220 − 55 = 165. HRR = 165 − 75 = 90. Zone 1 lower = (90 × 0.50) + 75 = 45 + 75 = 120. Zone 2 upper = (90 × 0.70) + 75 = 63 + 75 = 138.

Frequently asked questions

What is the Karvonen formula and why is it better than simple % of max HR?

The Karvonen formula incorporates your resting heart rate into the calculation, producing a personalised Heart Rate Reserve (HRR). Simple methods (e.g., Zone 2 = 60–70% of 190 bpm = 114–133 bpm) ignore how fit your heart is at rest. The Karvonen method yields higher, more accurate targets for fit individuals with low resting HR, and lower targets for those who are deconditioned.

How do I measure my resting heart rate accurately?

Measure your resting heart rate first thing in the morning, before getting out of bed. Count your pulse for 60 seconds at your wrist or neck, or use a chest-strap HR monitor. Average readings over 3–5 consecutive days for the most reliable value. Normal ranges are 60–100 bpm; well-trained athletes often fall between 40–60 bpm.

What should I train in Zone 2 for?

Zone 2 (60–70% HRR) is the aerobic base zone. It trains your body's mitochondrial density, fat oxidation efficiency, and slow-twitch muscle fibre endurance. Most elite endurance coaches recommend spending 70–80% of total training time in Zone 2. It improves long-term cardiovascular health, aids recovery, and builds the aerobic engine that supports higher-intensity work.

Is 220 minus age accurate for everyone?

The 220 − Age formula is a population average with a standard deviation of roughly ±10–12 bpm, so individual max HR can vary significantly. For most healthy adults it is a safe and practical starting point. More accurate alternatives include the Tanaka formula (208 − 0.7 × Age) for older adults, or performing a supervised maximal exercise test to measure your actual max HR directly.

How often should I train in Zone 5?

Zone 5 (90–100% HRR) is maximum-effort, anaerobic training. It should represent only 5–10% of total training volume. Most athletes incorporate 1–2 high-intensity interval (HIIT) sessions per week in Zone 4–5, separated by at least 48 hours of recovery. Excessive Zone 5 training without adequate recovery leads to overtraining, increased injury risk, and declining performance.

Can I use this calculator if I am on beta-blockers or heart medication?

Beta-blockers and certain other cardiac medications artificially lower your heart rate, making the standard 220 − Age formula unreliable. If you take heart rate–affecting medications, consult your doctor or a cardiac rehabilitation specialist who can prescribe personalised exercise intensity targets—often using perceived exertion (RPE) scales alongside or instead of heart rate zones.

Sources & references

External references open in a new tab. We are independent and not affiliated with these organizations.

  • ✓ Free to use
  • ✓ No sign-up required
  • ✓ Runs entirely in your browser — nothing is uploaded.
  • ✓ Formula and method shown above
Last updated: How we calculateReport a correctionDisclaimer

Provided “as is” for general information only — results may be inaccurate, so verify before you rely on them. No warranty; use at your own risk.

Built and reviewed by HIFreeTools against the formula shown above and any authoritative references cited on this page. See our methodology and editorial standards.

Related tools

Embed this tool on your site

Free to embed, no sign-up. Paste this code where you want the heart rate zone calculator to appear: