How to use the Calorie Calculator
- Enter your age, sex, height and weight.
- Choose the activity level that best matches a typical week.
- Press “Calculate” to see maintenance calories and weight loss or gain targets.
Formula used
BMR is estimated with the Mifflin-St Jeor equation, which research has found to be among the most accurate for healthy adults: men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5; women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161.
Daily energy needs (TDEE) are BMR multiplied by an activity factor: 1.2 (sedentary), 1.375 (light), 1.55 (moderate), 1.725 (very active), 1.9 (extra active).
Understanding the targets
- Maintain: calories to keep your current weight.
- Mild weight loss: about 250 kcal below maintenance (≈0.25 kg / 0.5 lb per week).
- Weight loss: about 500 kcal below maintenance (≈0.5 kg / 1 lb per week).
- Weight gain: 250–500 kcal above maintenance, ideally combined with strength training.
Minimum intake
Eating too little can make it hard to get enough nutrients. Health organizations commonly suggest not going below about 1,200 kcal per day for women and 1,500 kcal per day for men without medical supervision. The calculator warns you if a target falls below these levels.
Limits of these estimates
Formulas describe averages. Your real needs can differ by 10% or more depending on body composition, genetics, medical conditions and medications. Use the result as a starting point, track your progress for a few weeks and adjust. Pregnant or breastfeeding women, children, and people with medical conditions should ask a doctor or registered dietitian.
Examples
- A 30-year-old woman, 165 cm, 68 kg, moderately active: BMR ≈ 1,400 kcal, maintenance ≈ 2,170 kcal.
- A 40-year-old man, 180 cm, 90 kg, lightly active: BMR ≈ 1,830 kcal, maintenance ≈ 2,520 kcal.
Frequently asked questions
How many calories should I eat to gain weight?
Eat about 250–500 kcal above your maintenance calories and combine it with strength training, so most of the gain is muscle rather than fat.
How many calories should I eat to lose weight?
A common approach is about 500 kcal below your maintenance calories, which leads to roughly 0.5 kg (1 lb) of weight loss per week.
Which activity level should I choose?
Be conservative. Most people with desk jobs who exercise 2–3 times a week fit “Lightly active”.
Why does my weight not change as predicted?
Water, food volume and hormones cause day-to-day swings. Judge progress over 2–4 weeks and adjust by 100–200 kcal if needed.