Turning your energy needs into a daily calorie target
Knowing your TDEE is useful, but most people want a single actionable number: how many calories should I actually eat today to reach my goal? This calculator takes that extra step, starting from the same BMR and TDEE foundation used elsewhere on this site, then applying a goal-based adjustment to land on a practical daily target.
How the adjustment works
For weight loss, the calculator subtracts roughly 500 calories from TDEE — a moderate deficit that, based on the long-standing (if imperfect) "3,500 calories per pound of fat" rule of thumb, corresponds to losing around 0.5kg per week for most people. For weight gain, it adds about 350 calories, a smaller surplus chosen to favour lean tissue gain over rapid fat gain. Maintenance simply targets TDEE itself.
These are starting points, not universal laws. Actual fat loss or gain per calorie of deficit or surplus varies by individual — metabolic adaptation, water retention, digestive efficiency, and even sleep quality all nudge the real-world number in either direction. The right move is always to track results over two to three weeks and adjust the target based on what's actually happening on the scale and in the mirror, not to treat the formula's output as gospel.
Why macros matter alongside total calories
Total calories determine whether you gain, lose, or maintain weight — but macronutrient split shapes how that weight change feels and what kind of tissue you gain or lose. Protein is particularly important during a calorie deficit, helping preserve muscle mass that might otherwise be lost alongside fat; it's also the most satiating macronutrient, which helps with appetite control. The default 30/40/30 split (protein/carbs/fat) used here is a reasonable general-purpose starting point, weighted slightly toward protein compared to a typical Western diet.
Carbohydrates fuel high-intensity exercise and support training performance and recovery, while dietary fat is essential for hormone production and the absorption of fat-soluble vitamins. None of the three macronutrients should be eliminated entirely for most people — the right split is about balance and personal context (training style, medical considerations, food preferences) more than chasing a single "perfect" ratio.
Translating grams into a real day of eating
The macro numbers above are a planning tool, not a precision requirement. Hitting your protein target consistently matters more than hitting carbs or fat to the exact gram — protein is the macronutrient most strongly linked to muscle preservation and satiety, and the easiest one to fall short on without deliberate effort. A simple approach is to build meals around a protein source first, then fill in carbohydrates and fats around it based on appetite, training schedule, and food preference.
Common mistakes
The biggest mistake is picking too aggressive a deficit in pursuit of faster results. Very large deficits tend to increase hunger, reduce training performance, and raise the risk of losing muscle alongside fat — and they're harder to sustain for more than a few weeks, which often leads to rebounding. A second common mistake is recalculating the target too rarely; as weight changes meaningfully (5kg or more), BMR and TDEE shift too, and the original calorie target should be revisited.
References
Hall, K.D. & Guo, J. — Obesity Energetics: Body Weight Regulation and the Effects of Diet Composition, Gastroenterology · Academy of Nutrition and Dietetics — Macronutrient guidance