How to calculate your daily calorie needs
PlateSight team · Last updated: Wednesday, October 7, 2026
Whether you want to lose weight, gain weight or maintain it, the starting point is knowing how much energy you burn each day. This number is not exact; it is an estimate. But a good estimate lets you set a realistic goal and interpret your progress correctly.
The parts of daily energy expenditure
- Basal metabolic rate (BMR): The energy the body uses at rest to keep vital functions going. It is the largest part of the total.
- Movement: Exercise and all movement during the day: walking, standing, housework.
- Digestion of food: The energy used to digest what you eat; about one tenth of the total.
Step 1: Calculate your basal metabolic rate
One of the commonly used methods for adults is the Mifflin-St Jeor equation. It uses kilograms, centimeters and years:
- Men: (10 × weight) + (6.25 × height) − (5 × age) + 5
- Women: (10 × weight) + (6.25 × height) − (5 × age) − 161
Example: for a 35-year-old woman who is 165 cm tall and weighs 70 kg, 700 + 1,031 − 175 − 161 = about 1,395 kcal. This is close to the energy she would burn if she did not move at all during the day.
Step 2: Multiply by the activity factor
- Sedentary (desk job, no exercise): × 1.2
- Lightly active (light exercise 1–3 days a week): × 1.375
- Moderately active (exercise 3–5 days a week): × 1.55
- Very active (intense exercise 6–7 days a week): × 1.725
- Extremely active (physical job and two workouts a day): × 1.9
If the woman in the example walks three days a week, she burns 1,395 × 1.375 ≈ 1,920 kcal. This is her approximate need to maintain her weight. Most people overestimate their activity; if you are not sure, start with the lower factor.
Step 3: Adjust for your goal
To lose weight you need to eat slightly less than you burn, and to gain weight slightly more. A general approach is to subtract about 300–500 kcal from your daily need; for most people this means a slow, sustainable loss of about half a kilogram a week. Very large deficits increase hunger, fatigue and muscle loss and usually cannot be kept up for long.
For a weight gain goal, adding 250–500 kcal above your need and keeping protein adequate is a common starting point. In both cases you should look at your weight trend over a few weeks and update the target.
The limits of the calculation
- The formulas were developed on average people; they can be off for people with a high or low proportion of muscle.
- Needs are calculated differently during pregnancy, breastfeeding, growth years and some illnesses.
- The body changes over time: as you lose weight, your needs decrease too. Recalculate your target every few kilos.
After you set your goal
A calorie target only means something when it is tracked. Log your meals and look at your weekly average; the surplus or deficit of a single day does not determine the outcome. We explained how to divide energy among protein, carbohydrate and fat in our article on calculating macros.
When you use the PlateSight app for personal use, on first launch you are offered a daily calorie target based on your age, height, weight, activity and goal. The app does not set this target below a safe lower limit and does not offer a weight loss goal to people with a low body mass index. As you log your meals with photos, you see the day's total alongside your target. If you want to try it first, you can upload a meal photo in the Try your plate section.
Important: This article is for general information. For your personal goal, especially if you have a health condition or are experiencing rapid weight change, consult a dietitian.