How does calories in vs out affect weight?

Eating fewer calories than you burn creates a deficit and leads to weight loss; eating more creates a surplus and leads to gain. About 7700 kcal equals roughly 1 kg of body weight.

Why doesn't my real weight match the estimate?

Short-term weight swings come from water, glycogen and digestion. The estimate reflects the underlying fat trend over weeks, not day-to-day scale numbers.

Is this medical advice?

No. It is an educational estimate. For a personalised plan, speak to a doctor or registered dietitian.

Calories In vs Out Calculator

See your daily calorie balance and projected weight change.

Calories in vs out calculator

Weight change comes down to energy balance: calories in versus calories out. This calculator takes what you eat and what you burn each day and shows your daily deficit or surplus, the weekly total, and an estimated weight change — then flags whether it actually matches your goal.

It uses the standard rule that about 7,700 kcal equals roughly 1 kg of body weight. Everything runs in your browser, privately.