Target Heart Rate Calculator

220 minus age is a rule of thumb, not a measurement

The 220 − age formula has no clear published derivation and a standard error of about 10 to 12 beats per minute. That means for any given 40-year-old, a true maximum anywhere between roughly 158 and 202 is unremarkable. Tanaka's 208 − 0.7 × age came from a 2001 meta-analysis and fits older adults better; Gulati's was derived specifically in women, in whom the classic formula tends to overestimate. All three are still estimates.

What the Karvonen method adds

Karvonen works from heart rate reserve — the gap between resting and maximum — rather than from maximum alone: target = resting + (reserve × intensity). For someone with an average resting rate the two methods land close together. For a trained athlete resting at 45, or someone resting at 85, they diverge by ten beats or more, and the percentage method sends them to the wrong intensity.

The “fat burning zone” is real and misunderstood

At low intensity a larger proportion of energy comes from fat. At high intensity the proportion falls but the total energy burned rises, and the total is what changes body composition. Training easy has real benefits — it is sustainable, it builds aerobic base and it recovers faster — but “burns more fat” is not one of them once you compare equal sessions.

When a number should send you to a doctor

Chest pain, unusual breathlessness, dizziness or a heart rate that stays far above normal after exercise are reasons to stop and seek advice, whatever a calculator says. Anyone with a cardiac condition, on beta blockers, or returning to exercise after a long gap should have zones set by a clinician: beta blockers in particular lower both resting and maximum rates, which makes every formula on this page inapplicable.

Frequently Asked Questions