Heart Rate Zone Calculator
Enter your age and resting heart rate to find your 5 heart rate training zones for optimal exercise intensity.
Reviewed by the ToolNestr Editorial Team — July 2026
Enter your age and resting heart rate to see your zones.
About heart rate zone training
Heart rate zone training is one of the most effective ways to structure your exercise programme. By training at specific intensities, you can target different physiological adaptations. Zone 2 training builds your aerobic base and improves fat metabolism. Zone 3 (tempo) improves your lactate threshold. Zone 4 and 5 work on your anaerobic capacity and maximum power output. This calculator uses the Karvonen method (heart rate reserve), which is more personalised than the simple 220-minus-age formula because it accounts for your resting heart rate. For more ways to measure fitness, see the VO2 Max Calculator and Pace Calculator.
For general information only. Consult a doctor before starting a new exercise programme.
How it works
The calculator first estimates your maximum heart rate using the Tanaka formula (208 − 0.7 × age), which is more accurate than the traditional 220 minus age formula. It then calculates your Heart Rate Reserve (HRR = max HR − resting HR). Each zone is a percentage range of your HRR, added to your resting heart rate. For example, Zone 2 (60–70%) uses the formula: target HR = (HRR × 0.6) + resting HR to (HRR × 0.7) + resting HR. This method is personalised — a fit person with a low resting HR will have narrower zones than someone with a higher resting HR.
The formula explained
Max HR = 208 − 0.7 × age (Tanaka formula)
Heart Rate Reserve (HRR) = Max HR − Resting HR
Target HR = (HRR × intensity%) + Resting HR
The five zones are: Zone 1 (50–60%), Zone 2 (60–70%), Zone 3 (70–80%), Zone 4 (80–90%), Zone 5 (90–100%).
Worked example
A 35-year-old with a resting heart rate of 62 bpm wants to find their Zone 2 range.
Endurance runner
Use Zone 2 for long runs to build aerobic base without excessive fatigue. Most easy running should be in Zone 2.
Cyclist
Train with power and heart rate zones together. Zone 3 tempo efforts build sustainable speed for longer rides.
HIIT athlete
Use Zone 4–5 for intervals. The high-intensity efforts improve VO2 max and anaerobic capacity.
Cardiac rehab patient
Zone 1–2 training under medical supervision helps rebuild cardiovascular fitness safely after a cardiac event.
How to use this calculator
Enter your age
Your age is used to estimate your maximum heart rate using the Tanaka formula.
Measure resting HR
Take your resting pulse first thing in the morning for the most accurate result. Average over 3 mornings.
Train by zone
Use a heart rate monitor during workouts. Stay within the target zone range for each session type and adjust as your fitness improves.
Tips for zone training
Spend most time in Zone 2
The 80/20 rule suggests 80% of training should be easy (Zones 1–2) and 20% hard (Zones 4–5). This approach yields the best results for most athletes.
Re-test resting HR regularly
As your fitness improves, your resting HR drops, which shifts your zones. Re-measure your resting HR every 4–6 weeks to keep your zones accurate.
Use perceived exertion too
Heart rate can lag during short intervals and drift during long sessions. Combine zones with Rate of Perceived Exertion (RPE) for the most effective training intensity management.
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Frequently asked questions
What are heart rate zones?
Heart rate zones are intensity ranges expressed as a percentage of your maximum or reserve heart rate. Zone 1 (very light, 50-60%) through Zone 5 (maximum effort, 90-100%) help you train at the right intensity for your goals.
What is the Karvonen method?
The Karvonen formula uses your heart rate reserve (HRR = max HR minus resting HR) to calculate target zones. It is more personalised than simple percentage of max HR because it accounts for your resting heart rate.
How do I find my resting heart rate?
Measure your pulse first thing in the morning before getting out of bed. Count beats for 60 seconds. Do this for 3 mornings and average the results for the most accurate resting HR.
What is a normal max heart rate?
The traditional formula is 220 minus your age, but this has wide individual variation. A more accurate formula is 208 - 0.7 × age. Athletes may have higher or lower max HR than predicted.
Which zone should I train in?
Zone 2 (aerobic, 60-70%) builds endurance and is great for long sessions. Zone 3 (tempo, 70-80%) improves lactate threshold. Zone 4-5 (threshold/sprint) improves speed and power. Most training should be in Zones 2-3.