Calorie Deficit Calculator

A calorie deficit means eating fewer calories than your body burns in a day. When energy intake is lower than expenditure, your body makes up the difference from stored energy, mostly fat, which is how weight loss happens. A surplus is the opposite and supports weight gain.

Most guidance suggests losing about 0.5 to 1 percent of your body weight per week, which is roughly 0.25 to 1 kg (0.5 to 2 lb) for many people. Slower loss is easier to sustain and helps protect muscle. Going too aggressive often backfires with hunger, fatigue and rebound eating.

It is a useful starting estimate, not a law. The rule assumes about 3500 kcal per pound (7700 kcal per kg) of body fat, but real results vary because your metabolism adapts, water weight shifts and some loss is lean tissue. Treat the target as a hypothesis and adjust it based on the scale.

As you lose weight you burn fewer calories, so an old deficit can shrink to nothing. Daily water and food retention can also hide fat loss for weeks. Recheck your maintenance calories at your new weight, weigh trends over two to three weeks, and adjust intake or activity if the average is flat.

Maintenance calories, or TDEE, are the calories you burn in a day. Estimate them with a TDEE calculator from your weight, height, age, sex and activity, then refine the number by tracking your weight against your intake for a few weeks.

No. The calculation runs entirely in your browser. Nothing you enter is sent to a server or saved.