🥗 Health
Calorie Calculator
Find your resting metabolic rate, the calories you burn across a normal day and sensible targets for losing, maintaining or gaining weight. Press Calculate.
How these numbers are produced
Basal Metabolic Rate (BMR) is the energy your body uses at complete rest, estimated here with the Mifflin-St Jeor equation — the most accurate simple formula for most adults. Multiplying BMR by an activity factor gives TDEE, your total daily energy expenditure.
- Men: BMR = 10 × kg + 6.25 × cm − 5 × age + 5
- Women: BMR = 10 × kg + 6.25 × cm − 5 × age − 161
- TDEE = BMR × activity factor (1.2 to 1.9)
- About 7,700 kcal equals roughly 1 kg of body mass
Worked example
A 30-year-old woman weighing 65 kg at 165 cm has a basal metabolic rate of about 1,370 kcal a day using the Mifflin-St Jeor equation. With a light-activity multiplier of 1.375, her estimated daily energy need is roughly 1,884 kcal.
Everyday uses
- Estimating the calories needed to maintain your weight
- Planning a modest deficit for gradual weight loss
- Understanding why intake needs change as you age
- Comparing activity levels rather than guessing
- Sanity-checking a diet plan's headline numbers
Frequently asked questions
More worked examples
- A 70 kg, 175 cm, 30-year-old man has a resting requirement of about 1,649 kcal per day on the Mifflin-St Jeor formula.
- With light activity, multiplying by 1.375 gives a daily total of about 2,267 kcal.
- A deficit of 500 kcal per day corresponds roughly to 0.45 kg of body mass per week, because a pound of fat stores about 3,500 kcal.
- Protein and carbohydrate supply about 4 kcal per gram, fat about 9, and alcohol about 7.
Activity multipliers
| Activity level | Multiplier |
|---|---|
| Sedentary | 1.2 |
| Lightly active | 1.375 |
| Moderately active | 1.55 |
| Very active | 1.725 |
| Extra active | 1.9 |
Common mistakes to avoid
- Treating an estimate as a measurement. These formulas describe a population average and can be off by several hundred calories for one person.
- Cutting intake very aggressively. Large deficits are hard to sustain and tend to reduce lean mass as well as fat.
- Overestimating how much exercise burns. Thirty minutes of running is roughly 300 kcal, less than a single large pastry.
- Assuming food labels and scales are exact. Both carry measurement error that adds up over a week.
Further questions
Sources and limits
Resting energy expenditure is estimated with the Mifflin–St Jeor equation, published in 1990 and still one of the most widely used predictive formulas. Activity multipliers are population averages, not measurements: they cannot know your actual movement, muscle mass, medical conditions or metabolism.
- Mifflin et al. (1990) — A new predictive equation for resting energy expenditure
- Dietary Guidelines for Americans — official dietary guidance
- NHS — What should my daily intake of calories be?
What is a healthy weight for my height
The usual screen is BMI: a healthy range is 18.5 to 24.9, calculated as weight in kilograms divided by height in metres squared. For a 1.70 m adult that is roughly 53.5 kg to 72 kg; for 1.80 m it is about 60 kg to 80.6 kg.
| Height | Healthy weight range |
|---|---|
| 1.55 m (5 ft 1 in) | 44.5 – 59.8 kg |
| 1.60 m (5 ft 3 in) | 47.4 – 63.7 kg |
| 1.65 m (5 ft 5 in) | 50.4 – 67.8 kg |
| 1.70 m (5 ft 7 in) | 53.5 – 72.0 kg |
| 1.75 m (5 ft 9 in) | 56.7 – 76.3 kg |
| 1.80 m (5 ft 11 in) | 59.9 – 80.7 kg |
| 1.85 m (6 ft 1 in) | 63.3 – 85.2 kg |
BMI is a population screen, not a diagnosis: it does not distinguish muscle from fat, and athletes routinely sit above 24.9 while carrying little body fat. Waist circumference and body composition are better individual measures.