About this tool
The tool first estimates your resting energy use with the Mifflin-St Jeor equation, published in 1990 from measurements of 498 healthy adults aged 19 to 78. It then multiplies that by the range of physical activity levels the FAO, WHO and UNU give for your lifestyle.
Energy needs also change with illness, pregnancy, breastfeeding, medicines and body composition, so a dietitian or your GP can give advice that fits you.
Sources: American Journal of Clinical Nutrition, A new predictive equation for resting energy expenditure in healthy individuals (Mifflin and colleagues, 1990), read on 13 October 2026, and FAO, WHO and UNU, Human energy requirements, chapter 5: energy requirements of adults, read on 13 October 2026.