Calorie and TDEE calculator

How it works

How this calorie calculator works

First it estimates your basal metabolic rate (BMR), the energy your body uses at rest, with the Mifflin–St Jeor equation (1990). A 2005 systematic review in the Journal of the American Dietetic Association found it the most reliable of the common equations for healthy adults.

• Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
• Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161

It then multiplies BMR by an activity factor from 1.2 (mostly sitting) to 1.9 (heavy manual labor plus training) to estimate your total daily energy expenditure (TDEE), or maintenance calories. Your job counts. A standing or walking shift moves you up a level even if you don’t work out.

Example

A 30-year-old man who weighs 80 kg (176 lb) and is 180 cm (5′11″) has a BMR of 10×80 + 6.25×180 − 5×30 + 5 = 1,780 calories. With a moderate activity level (×1.55), his maintenance is about 2,759 calories a day.

What to do with the number

1. Eat close to the target for 2–3 weeks.
2. Weigh yourself a few mornings a week and look at the weekly average, not single days.
3. If the trend isn’t moving the way you want, adjust by 100–200 calories a day and repeat.

Equations are estimates. Real people vary by roughly 10% in either direction. Your scale trend is the real calculator. For a more detailed weight-change projection, the NIH’s Body Weight Planner models how your body adapts over time.

Questions people ask

What is TDEE?

Total daily energy expenditure: the calories you burn in a day from resting metabolism, digestion, daily movement (including work) and exercise. Eating at your TDEE keeps weight roughly stable.

How many calories should I eat to lose weight?

A gentle deficit of about 10–20% below maintenance is a common starting point. This calculator shows 15%. Larger deficits are harder to keep up, and going below your resting energy needs should be supervised by a clinician.

Is the Mifflin–St Jeor equation accurate?

It’s considered the most reliable of the common equations for healthy adults, but any equation is an estimate. Track your weight trend for a few weeks and adjust.

Why do I need to enter my sex?

The equation was built from data that differs by sex, so it uses a different constant for men and women. If neither option fits you, try both and use the average as a starting point.

Sources

1. Mifflin MD et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr, 1990.
2. Frankenfield D et al. Comparison of predictive equations for resting metabolic rate. J Am Diet Assoc, 2005.
3. FAO/WHO/UNU. Human energy requirements, 2001 (activity levels).
4. NIDDK Body Weight Planner (NIH).

Education only. Not medical advice. Confirm with your clinician.