Lifestyle
Food & Nutrition
FitnessFind out how many calories you need per day to lose, maintain, or gain weight.
This tool is for general information only and is not medical advice. Talk to a healthcare professional about results that concern you.
How Many Calories Do You Need Per Day?
Your daily calorie needs depend on four things: your size, your age, your sex, and how much you move. This calculator uses the Mifflin-St Jeor equation, which studies have repeatedly found to be the most reliable formula for estimating metabolism in the general population. It first works out your basal metabolic rate (BMR), the energy your body burns just staying alive, then multiplies it by an activity factor to get your total daily energy expenditure (TDEE).
TDEE is your maintenance number. Eat around it and your weight stays put. Eat below it and you lose weight. Eat above it and you gain. Every diet that has ever worked, from keto to intermittent fasting, works through this single mechanism.
Calories for Weight Loss
A deficit of 500 calories a day adds up to roughly 0.5 kg (1 lb) of weight loss per week. That pace is sustainable for most people and leaves enough food on the plate to meet protein and micronutrient needs. Cutting harder than that tends to backfire: hunger climbs, energy drops, and muscle loss speeds up.
Two guardrails worth keeping: women should generally not eat below 1,200 calories a day and men below 1,500 without medical supervision. And whatever your calorie target, keep protein high. Our protein calculator and macro calculator turn your calorie number into a full daily plan.
Frequently Asked Questions
How many calories should I eat a day?
Most women maintain their weight on roughly 1,800 to 2,200 calories a day and most men on 2,200 to 2,800, but the spread is wide. Your personal number from the calculator above is far more accurate than any general rule.
How many calories should I eat to lose weight?
Take your maintenance calories and subtract 250 to 500. That produces a loss of roughly 0.25 to 0.5 kg (0.5 to 1 lb) per week. The results table above shows these targets already calculated for you.
What is TDEE?
Total daily energy expenditure. It is everything you burn in 24 hours: your resting metabolism, digestion, daily movement, and exercise. TDEE is the number weight loss and weight gain plans are built around.
Should I eat back the calories I burn exercising?
If you selected an activity level that already includes your workouts, no. Your exercise is already counted. Only add calories back for unusual extra activity, and even then only about half of what your watch claims, since trackers overestimate.
Why am I not losing weight in a calorie deficit?
The most common reasons are underestimating portions, weekend overshooting, and water retention masking fat loss on the scale. Track honestly for two weeks and weigh yourself daily, then compare weekly averages before changing anything.
Sources
- BMR (Basal Metabolic Rate): What It Is & How To Calculate It · Cleveland Clinic
- About the Body Weight Planner – NIDDK · NIH (NIDDK)
- 10 ways to cut 500 calories a day: MedlinePlus Medical Encyclopedia · MedlinePlus
- Dietary Guidelines for Americans, 2025-2030 – Healthy People 2030 | odphp.health.gov · HHS ODPHP
This calculator is for general information only and is not a substitute for professional medical or dietary advice.