Most adults need somewhere between about 1,600 and 3,000 kcal a day, but your number depends on your sex, age, height, weight and activity. The simplest accurate method is to calculate your BMR (calories burned at rest), multiply it by your activity level to get your maintenance calories (TDEE), then subtract 250 to 500 kcal to lose weight or add about 300 to gain. The free Smart Diet App does this for you in seconds.
- BMR = calories your body burns at complete rest.
- TDEE = BMR × activity factor (1.2 to 1.9) = maintenance calories.
- Lose weight safely with a 250 to 500 kcal daily deficit.
- Avoid going below about 1,200 kcal (women) or 1,500 kcal (men) without medical supervision.
Step 1: Calculate your BMR
The Mifflin-St Jeor equation is widely used by dietitians 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
Step 2: Multiply by your activity level
| Activity level | Factor |
|---|---|
| Sedentary (desk job, little exercise) | 1.2 |
| Light (exercise 1 to 3 days a week) | 1.375 |
| Moderate (3 to 5 days a week) | 1.55 |
| Very active (6 to 7 days a week) | 1.725 |
| Athlete or heavy physical job | 1.9 |
A worked example
BMR = 10 × 82 + 6.25 × 172 − 5 × 30 + 5 = 1,750 kcal. TDEE = 1,750 × 1.375 = about 2,406 kcal. To lose about 0.5 kg a week, he would eat around 1,900 kcal a day.
Step 3: Adjust for your goal
| Goal | Daily change from TDEE | Expected result |
|---|---|---|
| Lose weight steadily | −500 kcal | About 0.45 kg (1 lb) a week |
| Lose slowly | −250 kcal | About 0.25 kg a week |
| Maintain | 0 | Stable weight |
| Build muscle | +250 to +300 kcal | Slow gain with strength training |
Why 500? About 7,700 kcal is roughly equal to 1 kg of body fat, so a 500 kcal daily deficit adds up to about 3,500 kcal (around 0.45 kg) a week.
Where should your calories come from?
- Protein: about 1.2 to 1.8 g per kg of body weight helps you keep muscle and stay full.
- Fat: roughly 25 to 30% of calories, mainly from oils, nuts and fish.
- Carbohydrates: the rest, ideally from rice, roti, oats, fruit and vegetables.
Why your calorie number is an estimate
Formulas are averages. Track your weight for 2 to 3 weeks: if it does not move in the direction you want, adjust by 100 to 200 kcal. Weigh yourself at the same time of day and look at weekly averages, not daily changes.
Calculate yours in 10 seconds
Enter your details in the free Smart Diet & Nutrition App to get your calories, macros, BMI, water target and a meal plan built around Bangladeshi or world food. Prefer a ready-made plan? Try our 7-day Bangladeshi diet chart.
Sources
- Mifflin MD et al. (1990): A new predictive equation for resting energy expenditure in healthy individuals
- World Health Organization: Healthy diet
Frequently asked questions
How many calories should I eat to lose weight?
Calculate your maintenance calories (TDEE) and eat about 250 to 500 kcal less per day. For many adults that falls between about 1,400 and 2,200 kcal, but it varies by person.
What is the difference between BMR and TDEE?
BMR is the energy you burn at complete rest. TDEE adds your daily activity and exercise, so it represents your maintenance calories.
Is 1,200 calories a day too low?
For many adults, especially men and active people, 1,200 kcal is too low. Women should generally not go below about 1,200 kcal and men below about 1,500 kcal without medical supervision.
How accurate are calorie calculators?
They give a good starting estimate. Track your weight for 2 to 3 weeks and adjust by 100 to 200 kcal if needed.
Free, no sign-up, works on any device.
Guides for this tool
Guide · 3 min readBangladeshi Diet Chart for Weight Loss: 7-Day Sample Plan
Guide · 3 min readHigh-Protein Bangladeshi Foods: A Simple Guide With a Sample Day
Guide · 4 min readHow Much Water Should You Drink a Day? A Simple Guide
Guide · 4 min readHow to Gain Weight Healthily: A Simple Plan for Underweight PeopleWant a tool, website or app like this for your business?
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