Estimated energy needs calculator
Explore estimated resting energy and illustrative activity adjustments, without a calorie or weight-loss target.
Understand the difference between energy used at rest and an illustrative day with activity. For adults aged 20–78, reflecting the original equation’s study age range.
How to use this result
The simplified Mifflin–St Jeor equation estimates resting energy expenditure in kcal/day: 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years), then +5 or −161. The original study used male and female groups. These coefficient labels describe that study, not gender identity; the equation does not account for hormone therapy or individual body composition. A dietitian can help if neither coefficient is appropriate for you.
The activity multipliers are broad heuristic scenarios, not part of the original equation or individually validated activity assessments. “Moderate” here is only a rough description, not an exercise prescription. We multiply resting energy by your chosen factor to illustrate how a daily estimate changes.
Do not use these estimates as a food intake target or to plan a calorie deficit. They may be inappropriate during pregnancy, breastfeeding, eating-disorder recovery, serious illness, or surgical recovery. Athletes and people with unusual body composition may need individual assessment. Actual needs vary.
Source: Mifflin et al. (1990), original resting energy equation.
Sources checked 21 October 2026. Educational information; discuss health decisions with a qualified healthcare professional.