Calculate Your Daily Calories
For adults 18+. Not for use during pregnancy or breastfeeding.
How It Works
First, the calculator estimates your basal metabolic rate (BMR), the calories your body uses at complete rest, with the Mifflin-St Jeor equation:
Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Then it multiplies BMR by an activity factor, from 1.2 for sedentary to 1.9 for extra active, to get your total daily energy expenditure (TDEE). The “steady fat loss” target is about 500 calories below that, which works out to roughly a pound a week for many people.
Using Your Number
- Track for two to three weeks before changing anything. Daily weight swings with water and food; the weekly trend is what counts.
- Watch your waist, not just the scale. A shrinking waist while weight holds steady usually means you're losing fat and keeping muscle. Check your waist-to-height ratio →
- Keep protein up and keep lifting while in a deficit so the weight you lose is mostly fat.
- Adjust in small steps. If nothing changes after three weeks, trim about 100 to 200 calories a day.
Very low calorie intakes are hard to sustain and can cost muscle and nutrients. Unless a doctor is supervising you, don't eat less than about 1,200 calories a day for women or 1,500 for men. If you have a medical condition or take medication, check with your doctor before changing your diet.
Frequently Asked Questions
What is TDEE?
Total daily energy expenditure is the number of calories you burn in a day: your resting metabolism plus everything you do on top of it, from walking to training. Eating at your TDEE keeps your weight roughly stable.
How accurate is this calculator?
It uses the Mifflin-St Jeor equation, which a review of resting-metabolism equations found to be the most accurate for most adults, typically within about 10% of measured values. Treat the result as a starting point and adjust based on how your weight and waist change over two to three weeks.
How many calories should I eat to lose weight?
A moderate deficit of about 300 to 500 calories a day below your TDEE leads to steady fat loss for most people. Bigger deficits make it harder to keep muscle and to stick with the plan.
Which activity level should I choose?
Most people overestimate their activity. If you have a desk job and train three or four times a week, “moderately active” is usually closer than “very active.” If your weight doesn't move as expected, step down one level.
Working Toward a Military Standard?
Find the maximum waist for your height under the Army's 0.55 rule.
Open the Army Waist Chart →📚 Sources
- Mifflin, M. D., St Jeor, S. T., Hill, L. A., Scott, B. J., Daugherty, S. A., & Koh, Y. O. (1990). A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 51(2), 241–247.
PubMed → - Frankenfield, D., Roth-Yousey, L., & Compher, C. (2005). Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association, 105(5), 775–789.
PubMed →