Heart Rate Zone Calculator
Target heart rate zones for training.
About this tool
Heart rate zones translate the abstract idea of "training intensity" into a number you can see on your watch. This calculator uses the Tanaka equation (208 − 0.7 × age), which is more accurate than the older 220 − age formula, especially after age 40.
If you add your resting heart rate, zones use the Karvonen heart rate reserve method, which is more personalised.
Frequently asked questions
Which zone should I train in?
Most weeks: 70–80% in Zone 2 (easy, conversational), 10–20% in Zone 4–5 (hard intervals), and the rest in tempo or recovery. This 'polarised' distribution is what elite endurance athletes use.
Why is Zone 2 so popular?
It builds mitochondrial density and aerobic base without the recovery cost of high-intensity work. You can do a lot of it without burning out.
What if I take beta-blockers?
Beta-blockers cap your heart rate. The formula will overestimate your max — use rating of perceived exertion (RPE 1–10) instead.
⚕️ Educational only — not a substitute for professional medical advice, diagnosis, or treatment. In an emergency call your local emergency services.