How weight loss works
Weight loss comes down to energy balance: eat fewer calories than you burn, and your body draws on stored fat to make up the difference. About 7,700 calories equals roughly one kilogram (3,500 per pound) of body fat, which is how a daily target translates into weekly progress.
How this calculator works
First we estimate your TDEE — the calories you burn per day — from your details and activity level. Then, from your goal weight and timeframe, we work out the daily deficit needed and show your target intake. If the pace is too aggressive or the target dips below a safe floor, you'll see a warning.
A safe, realistic pace
A loss of about 0.5–1 kg (1–2 lb) per week is widely considered safe and sustainable. Faster than that and you risk losing muscle, feeling drained and rebounding. As a rule, don't eat below roughly 1,500 calories (men) or 1,200 (women) without medical supervision.
Keeping it off
The deficit gets you there; habits keep you there. Prioritise protein (see the protein calculator), strength-train to protect muscle, and recalculate as your weight drops — your TDEE falls as you get lighter, so targets need updating.
Helpful tools
Weigh portions so your deficit is real, not guessed.
View options →Log meals and stay accountable to your target.
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Frequently asked questions
How many calories should I cut to lose weight?
Enough to create a deficit below your TDEE. A 500-calorie daily deficit yields about 0.5 kg (1 lb) of loss per week, a pace most people can sustain.
Is it safe to lose weight fast?
Rapid loss risks muscle loss, fatigue and rebound weight. Most guidance favours 0.5–1 kg (1–2 lb) per week, and not eating below about 1,200–1,500 calories without medical advice.
Why do I need to recalculate as I lose weight?
Your TDEE falls as you get lighter, so the calorie target that worked at the start will eventually stall progress. Recalculate every few kilograms.
Do I have to count calories forever?
No. Counting helps you learn portion sizes and build awareness. Many people transition to habit-based eating once they understand their targets.