Tools
Calorie Intake Calculator
Find your daily calorie needs
How we calculate your calorie needs
This calculator uses the Mifflin-St Jeor equation, which research published in the Journal of the American Dietetic Association has identified as the most reliable formula for estimating Basal Metabolic Rate (BMR) in healthy adults. BMR represents the calories your body burns at complete rest to maintain vital functions like breathing, circulation, and cell repair. The formula is: For men: BMR = 10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5. For women: BMR = 10 x weight (kg) + 6.25 x height (cm) - 5 x age - 161. Your BMR is then multiplied by one of three activity factors — 1.2 (not much), 1.55 (some) or 1.725 (a lot) — to estimate your Total Daily Energy Expenditure (TDEE). These are the same three levels the Klem app uses, so the number here is the number the app will hold for you. For weight loss the calculator applies a pace of 0.5 kg per week, which is a deficit of about 550 kcal per day. NIH guidance uses a deficit of about 500 kcal per day; Klem sets about 550, which is 0.5 kg per week. For weight gain the same amount is added. The result never goes below 1,500 kcal for men, 1,200 kcal for women or 1,350 kcal otherwise. Treat it as a starting point and adjust to how your weight actually moves.
What your result means
Your recommended calorie intake is a personalized estimate based on your age, sex, height, weight, activity level, and goal. A daily deficit of about 550 calories typically produces approximately 0.5 kg (1 lb) of weight loss per week. NIH guidance uses a deficit of about 500 kcal per day; Klem sets about 550, which is 0.5 kg per week and is considered a safe and sustainable rate. For weight gain, a surplus of about 550 calories per day supports gradual lean mass increases when combined with resistance training. It is important to note that these are evidence-based starting points, not exact prescriptions. Individual metabolism varies due to genetics, hormonal factors, sleep quality, stress levels, and body composition. Your actual calorie needs may be 10 to 15 percent higher or lower than the estimate. The most effective approach is to follow your recommended intake for two to four weeks, monitor your weight trend, and then adjust up or down by 100 to 200 calories as needed. Avoid dropping below 1,200 kcal per day for women or 1,500 kcal per day for men without medical supervision, as very low intakes can impair metabolic function.
Frequently Asked Questions
What is the Mifflin-St Jeor equation?
The Mifflin-St Jeor equation is the most widely validated formula for estimating Basal Metabolic Rate (BMR), according to a comparative study published in the Journal of the American Dietetic Association. It accounts for weight, height, age, and sex. Compared to older formulas like Harris-Benedict, it provides more accurate estimates for modern populations and is recommended by the American Dietetic Association for clinical use.
How many calories should I eat to lose weight?
A daily deficit of about 550 calories from your TDEE typically results in about 0.5 kg (1 lb) of weight loss per week. It's not recommended to eat below 1200 kcal/day for women or 1500 kcal/day for men without medical supervision.
Should I eat back exercise calories?
It depends on your goal and how active you are. If you are trying to lose weight, you generally should not eat back all exercise calories, since calorie burn estimates are often overestimated. If you exercise intensely and experience persistent fatigue, eating back 50 to 75 percent of exercise calories is a reasonable approach. The Klem app helps you track both food intake and activity so you can find the right balance.
How accurate is this calculator?
The calculator provides a solid estimate based on the Mifflin-St Jeor equation, which is accurate to within about 10 percent for most people. However, individual variations in metabolism, genetics, body composition, hormonal health, and actual activity intensity can cause your true needs to differ. Use the result as a starting point, track your weight over two to four weeks, and adjust your intake by 100 to 200 calories if progress stalls or moves too quickly.
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