Target Heart Rate Calculator

Training by feel works, but training by heart rate adds precision — it keeps your easy days genuinely easy and your hard days appropriately hard. This calculator gives you all five training zones, from recovery to maximum effort. Add your resting heart rate and it switches to the more accurate Karvonen method, which personalises the zones to your fitness. Maximum heart rate is estimated with the modern Tanaka equation (208 − 0.7 × age), not the dated “220 minus age”.

The five training zones

Each zone targets a different adaptation. A smart programme spends most time in the easy-to-moderate zones and only a little at the top.

Why the Karvonen method is more accurate

The simplest zone calculations use a flat percentage of your maximum heart rate. The Karvonen method goes further: it works from your heart-rate reserve — the gap between your resting and maximum heart rate — so it accounts for your fitness. A fitter person with a lower resting heart rate gets different, more personalised zones. That is why adding your resting HR above produces a more individual result.

The truth about the “fat-burning zone”

You will often see Zone 2 (around 60–70% of max) labelled the “fat-burning zone”, because a higher proportion of energy there comes from fat. It is genuinely useful for pacing easy aerobic work — but do not over-read it. Higher-intensity training burns more total calories, and often more total fat, per session. For fat loss, the deciding factors are total calories burned and your overall diet, not staying in one heart-rate band.

Using your zones

Most endurance progress comes from spending the bulk of your time in Zones 1–2 and reserving Zones 4–5 for shorter, harder efforts. To put this into practice, see HIIT vs steady cardio, follow our 5K training plan, and time your intervals with the interval timer.