Energy estimator

Estimate adult resting energy (BMR) with the Mifflin–St Jeor equation and a maintenance energy range based on activity level, with clear limitations.

Confirm you are an adult and not pregnant or breastfeeding — the equation isn’t designed for those situations.
Choose units, then enter your age, height and weight.
Choose the equation version (female or male) and the activity level that best matches a typical week.
Select Estimate. You’ll see estimated resting energy and a maintenance range. Nothing is saved.

About you

Fill in the form to see estimated resting energy and a maintenance range.

About this tool

How the estimate is calculated

Resting energy (BMR) uses the Mifflin–St Jeor equation, which predicts the energy your body uses at rest:

Male equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5
Female equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161

Estimated maintenance energy multiplies resting energy by a physical activity level (PAL). We use the lifestyle ranges from the FAO/WHO/UNU expert report on human energy requirements: 1.40–1.69 (sedentary or light activity), 1.70–1.99 (active or moderately active) and 2.00–2.40 (vigorous). Because nobody’s activity fits a single number, the result is shown as a range. Results are rounded to the nearest 10 calories.

How accurate is it?

In a systematic review, Mifflin–St Jeor predicted resting metabolic rate within 10% of measured values more often than other common equations, but it was still off by more than 10% for a meaningful share of people. Real needs also vary with body composition, health conditions, medications and day-to-day activity. Treat these numbers as a rough starting point, not a prescription.

This estimator is for adults only. Don’t use it for children or teens, during pregnancy or while breastfeeding, and don’t use it to set very low calorie targets. A doctor or registered dietitian can help you plan any change to how you eat.