Calorie Deficit Calculator

BMR (Basal Metabolic Rate) is the calories your body burns at complete rest. TDEE (Total Daily Energy Expenditure) multiplies BMR by your activity level to estimate daily calorie burn.

A 1kg/week deficit (~1100 kcal/day) is aggressive and should only be done under medical supervision. Most people do best at 0.5kg/week. Consult a healthcare professional before starting any diet.

Yes, the Calorie Deficit Calculator is 100% free with no registration, no hidden fees, and no usage limits. All processing happens locally in your browser, ensuring complete privacy.

Yes, the Calorie Deficit Calculator is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.

No account or registration is needed. Simply open the Calorie Deficit Calculator in your browser and start using it immediately. There are no sign-up walls or usage restrictions.

Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.

The Calorie Deficit Calculator works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.

Your weight-loss calorie target is your maintenance level (TDEE) minus a deficit sized to how fast you want to lose. Because roughly 7,700 kcal equals about one kilogram of body fat, a 0.5 kg/week loss needs about a 550 kcal/day deficit, while 0.25 kg/week needs around 275 and 1.0 kg/week around 1,100. So if your TDEE is 2,450 kcal, a moderate target lands near 1,900 kcal/day. There is no single number that fits everyone — it depends on your age, gender, height, weight, and activity level. For most adults, 0.5 kg/week is a sustainable default that protects muscle and energy. Enter your details into the Calorie Deficit Calculator and it returns your exact target, BMR, and TDEE in one step, with metric or imperial units.

It uses the Mifflin-St Jeor equation, one of the more accurate predictive formulas for resting metabolism. First it finds your BMR (calories burned at complete rest): 10 x weight(kg) + 6.25 x height(cm) - 5 x age, then +5 for men or -161 for women. It then multiplies that BMR by an activity factor to estimate your TDEE — 1.2 for sedentary, 1.375 lightly active, 1.55 moderately active, 1.725 very active, and 1.9 for extra-active jobs or athletes. Your daily target is simply TDEE minus your chosen deficit. These are established equations rather than rough rules of thumb, but they remain estimates. Pick the activity level that honestly matches your week, then read off your BMR, TDEE, and target instantly in the calculator above.

This calculator splits your target into 30% protein, 40% carbohydrate, and 30% fat, then converts each to grams using 4 kcal per gram for protein and carbs and 9 kcal per gram for fat. Protein gets nearly a third of the budget on purpose: eating enough protein during a deficit helps preserve lean muscle and keeps you fuller, so more of your weight loss comes from fat. Treat the 30/40/30 split as a balanced starting point, not a strict rule — you can shift carbs and fat to match your appetite, training, and preferences while keeping protein roughly steady. There is no single perfect ratio for everyone. Enter your stats and the tool shows your daily protein, carb, and fat grams alongside your calorie target so you can plan meals that actually add up.

The tool applies a hard floor of 1,200 kcal per day regardless of your inputs, because eating far below that risks nutrient shortfalls, muscle loss, fatigue, and an unsustainable diet. If your TDEE minus your chosen deficit would fall under 1,200, the calculator caps the target at 1,200 rather than showing a dangerously low number. This is a safety guardrail, not personalized medical advice: as a general guide, women should not drop below 1,200 kcal/day and men below 1,500 kcal/day without medical supervision. If your math keeps hitting that floor, it usually means your chosen pace is too aggressive for your size — picking a slower goal is safer and more durable. Always consult a healthcare professional before starting any diet, especially with an underlying health condition. The calculator surfaces this reminder right beside your results.

Treat every number here as a solid estimate, not an exact measurement. Predictive formulas like Mifflin-St Jeor can be off by 10% or more for any individual, and the activity multipliers are broad buckets rather than precise readings of how much you actually move. Real-world weight loss also rarely follows a straight line because water retention, hormones, sleep, and day-to-day adherence all shift the scale. That does not make the target useless — it gives you a concrete number to plan meals against and track honestly, which beats guessing. The practical approach is to use the result as a starting point, weigh yourself over weeks rather than days, and adjust if progress stalls or moves too fast. Run your details through the Calorie Deficit Calculator to get that baseline, then refine it from your own real-world results.