How a calorie calculator to lose weight works
The calorie calculator to lose weight does three things in sequence. First, it estimates your basal metabolic rate (BMR) with the Mifflin-St Jeor equation — the most widely validated modern BMR formula. Second, it multiplies BMR by an activity factor to get your total daily energy expenditure (TDEE), the number of calories you burn on a normal day. Third, it subtracts a deficit sized to your chosen weekly loss rate, capped at a sensible floor so the target never drops below safe territory.
The 7,700-calorie-per-kilogram rule
A kilogram of body tissue stores roughly 7,700 calories of energy (about 3,500 per pound). On paper that means a 1,100 calorie daily deficit averages out to 1 kg of fat loss per week. In practice metabolism is not a perfect spreadsheet — as you lose weight, you also lose a little muscle, your maintenance falls, and you move a little less throughout the day. So this rule is a decent first-approximation, not a guarantee.
Picking a sensible deficit
Health authorities — the CDC, the NHS, the American College of Sports Medicine — all recommend losing about 0.5 to 1% of body weight per week. That works out to a deficit of roughly 300–600 calories a day for most adults. Going much harder than that for long stretches usually backfires: hunger climbs, training quality drops, sleep gets worse, and the diet ends. Slow and consistent beats fast and fragile every time.
Plateaus, and what to do about them
Almost everyone hits a plateau. As you lose weight, your maintenance drops with you, so a diet that produced a 500 calorie deficit at 95 kg might only produce a 350 calorie one at 85 kg. The fix is not to drop calories aggressively right away — first add 1,000–2,000 daily steps and check that your weekly average has truly flattened over four weeks. If it has, knock 100–150 calories off the target and continue.
Why protein still matters when losing weight
A higher protein intake during a cut does two important things: it keeps you fuller per calorie, and it spares more muscle as you lose fat. Sports nutrition reviews settle on roughly 1.6–2.2 g of protein per kg of body weight per day; this calculator suggests about 2.0 g/kg, on the upper end of the band, because preserving muscle while in a deficit is harder than in maintenance.
Use with the rest of the site
Pair this target with the macro calculator to plan grams of protein, carbs and fat. Track what you eat with the food calorie calculator, and watch your progress in fair percentage terms with the weight loss percentage calculator.