How many calories should I eat per day?
A clinical walkthrough of energy balance, TDEE, and how to set a calorie target you can actually hold.
Your daily calorie target is your Total Daily Energy Expenditure (TDEE) adjusted for your goal: roughly maintenance for weight stability, a 15–20% deficit to lose fat, or a 10–15% surplus to gain lean mass. TDEE is your resting metabolism multiplied by an activity factor.
The short answer
Your daily calorie target is your Total Daily Energy Expenditure (TDEE) adjusted for your goal: roughly maintenance for weight stability, a 15–20% deficit to lose fat, or a 10–15% surplus to gain lean mass. TDEE is your resting metabolism multiplied by an activity factor.
How clinicians estimate it
The Mifflin–St Jeor equation predicts resting energy expenditure from your sex, weight, height and age, then an activity multiplier (1.2 sedentary to 1.9 athlete) scales it to real life. It is the most accurate predictive equation for non-obese adults and carries about a ±10% margin versus laboratory calorimetry.
Turning the number into a plan
Set protein first (1.6–2.2 g/kg), fats next (~25–30% of calories), and fill the rest with carbohydrate. Track your real-world response for two to three weeks and adjust — a calculator gives the starting point, not the final answer.
Linked calculators
Mifflin MD, St Jeor ST, et al. Am J Clin Nutr. 1990 · Tanaka H, et al. J Am Coll Cardiol. 2001 · Morton RW, et al. Br J Sports Med. 2018 · Reviewed by Dr. Lena Okafor, MD (Endocrinology), Feb 2026.