Estimated Energy Requirement Calculator

What is the estimated energy requirement?

The estimated energy requirement (EER) is the average number of calories a person of a given age, sex, size and activity level needs each day to stay at a steady weight. The term comes from the Dietary Reference Intakes published by the US Institute of Medicine (now the National Academy of Medicine), which use it to plan diets for healthy people.

It is an average for a group of similar people, so your own requirement can be a few hundred calories higher or lower. Treat the figure as a starting point, and adjust after watching what your weight does over two or three weeks.

How to use the calculator

1. Type your age in years and choose male or female.
2. Enter your height: feet and inches in US units, or centimetres (or metres) in metric units.
3. Enter your weight in pounds or kilograms.
4. Choose the activity level that fits a normal week, from sedentary to extreme.
5. Press Calculate EER.

The first line is your EER, the calories per day that should maintain your current weight. The next four lines, marked with an asterisk, are rough targets for losing 1 or 2 pounds (or 0.5 or 1 kg) a week and for gaining 0.5 or 1 pound (or 0.5 or 1 kg) a week. The last line is your basal metabolic rate (BMR), the energy your body uses at complete rest.

How the estimate is calculated

This calculator uses the Mifflin-St Jeor equation for BMR, which has been shown in validation studies to track measured resting energy use well in healthy adults, and multiplies it by an activity factor.

BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 (men)

BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161 (women)

EER = BMR × activity factor

The weight-change lines subtract or add a fixed amount to the EER: 500 and 1,000 calories a day below it for losing weight, and 500 and 1,000 above it for gaining. The rule behind this is that a pound of body weight is roughly 3,500 kcal, so a 500 kcal daily difference is about a pound per week.

Worked examples

A 45-year-old man, 6 ft tall (182.9 cm), weighing 200 lb (90.7 kg), mostly sedentary:

• BMR = 10 × 90.72 + 6.25 × 182.88 − 5 × 45 + 5 = 1,830 kcal.
• EER = 1,830 × 1.2 = 2,196 kcal a day.
• To lose a pound a week: 2,196 − 500 = 1,696 kcal. To lose two pounds: 1,196 kcal, which is low enough that it needs medical supervision.

A 34-year-old woman, 168 cm, 64 kg, exercising three to five times a week:

• BMR = 10 × 64 + 6.25 × 168 − 5 × 34 − 161 = 1,359 kcal.
• EER = 1,359 × 1.55 = 2,106 kcal a day.
• Losing half a kilogram a week: 1,606 kcal. Gaining half a kilogram a week: 2,606 kcal.

The official Dietary Reference Intake equations

The Institute of Medicine derived its own EER equations for adults from doubly labelled water studies. Age is in years, weight in kilograms and height in metres, and PA is a physical activity coefficient.

men (19 and older): EER = 662 − 9.53 × age + PA × (15.91 × weight + 539.6 × height)

women (19 and older): EER = 354 − 6.91 × age + PA × (9.36 × weight + 726 × height)

The coefficient is 1.00 for sedentary people and rises to about 1.11 and 1.25 for low active and active men (1.12 and 1.27 for women), and to 1.48 for very active men (1.45 for women). Different methods answer slightly different questions: for the 34-year-old woman above, the Institute of Medicine equation gives about 2,156 kcal with the low active coefficient and 2,429 kcal with the active one, against 2,106 kcal from the approach used here. Differences of a few hundred calories between methods are normal, which is another reason to treat any estimate as a starting point.

What changes your energy needs

• Body size and composition. Larger bodies, and bodies with more muscle, burn more energy at rest.
• Age. Resting energy use drifts down over adulthood, partly because lean mass declines.
• Sex. On average, men have more lean mass and a higher requirement at the same weight.
• Activity. Exercise and a physically demanding job can add several hundred calories or more per day.
• Pregnancy and breastfeeding. The Dietary Reference Intakes add roughly 340 kcal a day in the second trimester and 450 in the third, and about 330 to 400 kcal while breastfeeding.
• Health and environment. Illness, some medications, thyroid status and extreme temperatures all play a part.

A related tool, the TDEE calculator, estimates total daily energy expenditure the same way. For a breakdown into protein, carbohydrate and fat, see the macronutrient calculator and the carbs calculator. The BMR calculator and calorie calculator cover related questions, and the weight loss calorie calculator plans a timeline.

The asterisk marks a rough guideline. Very low calorie intakes (commonly cited floors are about 1,200 kcal a day for women and 1,500 for men) should only be followed under medical supervision. The results are estimates, not medical advice. See our disclaimer.