Find out exactly how many calories to eat per day to reach your goal weight
To lose weight, you need to consume fewer calories than you burn. Your TDEE (Total Daily Energy Expenditure) is how many calories your body burns at rest plus activity. Eating below your TDEE creates a deficit. Roughly 7,700 calories = 1 kg of fat. A 500 cal/day deficit = about 0.5 kg/week weight loss.
This tool uses the Mifflin-St Jeor equation, considered the most accurate for most adults.
The Calorie Deficit Calculator finds your daily calorie target for weight loss by working out your Total Daily Energy Expenditure (TDEE) and subtracting a deficit sized to your goal. Enter your age, sex, height, current weight, goal weight, and your activity level — from sedentary (desk job, little exercise) to very active (intense training six or more days per week). The calculator uses the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate (BMR) and multiplies it by an activity factor to get your TDEE. It then applies a calorie deficit to produce a daily intake target and an estimated time to reach your goal weight based on the energy deficit created.
The fundamental principle of weight loss is an energy deficit: when you consume fewer calories than your body burns, it must draw on stored energy — primarily body fat — to make up the difference. One kilogram of body fat contains approximately 7,700 kilocalories of stored energy. So to lose one kilogram, you need to create a cumulative deficit of about 7,700 kcal — roughly equivalent to cutting 500 kcal per day for 15 days, or 250 kcal per day for a month. In practice, weight loss is not perfectly linear because your metabolism adapts to your reduced intake, water retention fluctuates, and muscle mass changes can affect body composition without showing on the scale. However, maintaining a consistent daily deficit remains the most reliable driver of fat loss over time.
Most nutrition experts recommend a deficit of 500–750 kcal per day for sustainable weight loss — roughly 0.5–0.75 kg per week. Larger deficits accelerate weight loss in the short term but risk muscle loss, nutritional deficiencies, fatigue, and rebound eating. Very low calorie diets (below 800 kcal/day) should only be followed under medical supervision. The calculator flags unsustainably aggressive targets and suggests a safer alternative if your goal would require going below recommended intake floors. Regardless of the calorie target, the quality of your diet — adequate protein (to preserve muscle), plenty of vegetables, and sufficient micronutrients — matters at least as much as the number itself.
A deficit of 500–750 kcal per day produces around 0.5–0.75 kg of weight loss per week, which most nutritionists consider a safe and sustainable rate. Deficits larger than 1,000 kcal/day are generally not recommended without medical supervision, as they increase the risk of muscle loss and nutritional deficiencies.
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — the energy needed to keep your heart beating, lungs breathing, and organs functioning. TDEE (Total Daily Energy Expenditure) adds your activity level on top of BMR to give the total calories you burn in a typical day. Your calorie target for weight loss should be below your TDEE, not your BMR.
As your body weight decreases, your BMR decreases too — there is less mass to keep alive and move around. This means your TDEE falls as you lose weight, which is why weight loss often slows down over time even without any change in diet. Recalculating your TDEE every 5–10 kg of weight loss (or whenever you reach a plateau) keeps your target accurate.
In a calorie deficit, protein becomes especially important because it preserves lean muscle mass. Most recommendations suggest 1.6–2.2 grams of protein per kilogram of body weight per day when in a calorie deficit with exercise. Adequate protein also increases satiety, helping you stick to your calorie target without feeling as hungry.
Yes. Calorie counting is one approach but not the only one. Some people achieve a deficit through food quality changes (eliminating ultra-processed foods, eating more protein and fibre, drinking more water) without tracking every calorie. However, knowing your approximate calorie target is useful for understanding whether a particular diet approach is likely to create the deficit you need.
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