Daily calorie intake
There is no universal norm: it depends on weight, height, age, sex, and activity level. It takes a couple of minutes to calculate — and requires verification in practice.
Step 1. Basal metabolic rate
This is energy expenditure at rest — what is spent on breathing, blood circulation, and maintaining body temperature. The most commonly used formula is Mifflin-St Jeor:
Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5
Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161
Example: a 30-year-old woman, 70 kg, 165 cm. 10 × 70 + 6.25 × 165 − 5 × 30 − 161 = 700 + 1031 − 150 − 161 ≈ 1420 kcal.
Step 2. Activity factor
The basal metabolic rate is multiplied by a factor that reflects your entire lifestyle, not just workouts:
| Lifestyle | Factor |
|---|---|
| Sedentary, no exercise | 1.2 |
| Light activity, 1–3 workouts per week | 1.375 |
| Moderate, 3–5 workouts | 1.55 |
| High, 6–7 workouts | 1.725 |
| Very high, physical labor | 1.9 |
For the example above with a sedentary job and some walking: 1420 × 1.375 ≈ 1950 kcal — this is the maintenance level for weight.
Step 3. Adjustment for your goal
- Weight maintenance — maintenance level without changes.
- Weight loss — minus 300–600 kcal. This provides 0.5–1% of body weight per week. A larger deficit increases the proportion of muscle lost rather than the speed of results.
- Weight gain — plus 200–400 kcal combined with strength training.
For the example: weight loss — approximately 1500–1650 kcal per day.
Why the formula is just the beginning
Any formula provides an estimate with a margin of error: real expenditure for two people with identical parameters differs, and the difference can be significant. It is influenced by body composition, hormonal background, and habitual daily movement.
Therefore, the calculation must be verified in practice. Maintain the calculated calorie intake for two weeks, monitoring your average weekly weight rather than individual weigh-ins:
- weight does not change, and the goal is weight loss → decrease by 150–200 kcal;
- weight drops faster than 1% of body mass per week → increase intake, as losses are not just from fat;
- weight drops by 0.5–1% → everything is correct, do not change anything.
Practical difficulty
The norm is calculated in two minutes, but comparing actual consumption against it has to be done every day — and that is usually where it all ends. Analyzing a meal from a photo removes the bulk of this work: there is no need to search for items in a database or break down homemade food into ingredients.
Frequently asked questions
- How to calculate daily calorie intake?
- Calculate your basal metabolic rate using the Mifflin-St Jeor formula, multiply it by an activity factor from 1.2 to 1.9, and adjust for your goal: minus 300–600 kcal for weight loss, plus 200–400 for weight gain.
- How many calories does a woman need per day?
- It depends on weight, height, age, and activity level. For a 30-year-old woman, 70 kg, and 165 cm with a sedentary lifestyle, weight maintenance is about 1950 kcal, and weight loss is approximately 1500–1650 kcal. You should calculate based on your own parameters.
- How accurate are these formulas?
- This is an estimate with a noticeable margin of error: real expenditure for people with identical parameters differs. The calculation should be viewed as a starting point and adjusted based on your average weight over two weeks.
Read next
- What is KBZHU — KBZHU represents four numbers that describe food: caloric content and the three macronutrients that make it up.
- Calorie deficit: how to calculate it and how to hold it — A calorie deficit is the one thing without which weight does not come down.
- How to determine portion size without a scale — Portion weight is the most inaccurate variable in any calculation, including analysis by photo.
This article is for general information. It is not medical advice, a diagnosis, or a prescription for treatment or a diet, and it does not replace a consultation with your doctor. If you have a health condition, are pregnant, take medication, or follow a diet prescribed to you, decisions about food belong with your doctor.
Figures from regulations, guidelines and studies are given as they stood when this article was prepared and may since have changed; check them against the primary sources. This article is not advertising, an offer, or individual advice, and neither the author nor the site owner is responsible for decisions taken on the basis of it.