Calorie Deficit Calculator

How a calorie deficit works

1. 01

   Find maintenance

   We estimate the calories that hold your weight steady (your TDEE) from the Mifflin-St Jeor equation and your activity level.

2. 02

   Subtract a deficit

   Eating fewer calories than you burn is a deficit. Roughly 7,700 kcal equals about 1 kg of body mass, so a 550 kcal daily deficit is about 0.5 kg a week.

3. 03

   See your timeline

   Pick a pace and we show the daily target and how many weeks it takes to reach your goal — capped at a safe minimum so it stays realistic.

Questions

What is a calorie deficit?

A calorie deficit means eating fewer calories than your body uses in a day. That shortfall is made up from stored energy, which is how weight loss happens.

How big should my calorie deficit be?

A common, sustainable range is about 10–20% below maintenance, or roughly 250–500 kcal a day for around 0.25–0.5 kg of loss per week. Larger deficits work faster but are harder to sustain and can cost muscle.

How many calories is 1 kg of fat?

Body mass change is often estimated at about 7,700 kcal per kg (roughly 3,500 kcal per pound). It's an approximation — real loss includes water and lean tissue and isn't perfectly linear.

What's the lowest I should eat?

Very low intakes are hard to sustain and can be unsafe. This calculator holds the target at a commonly cited floor of about 1,200 kcal for women and 1,500 for men. For anything more aggressive, talk to a professional.

Why is my weight loss slower than the calculator says?

Estimates assume a steady deficit and average energy density. Water shifts, training, and metabolic adaptation all cause week-to-week noise. Judge progress over 2–3 weeks, not day to day.

Keep going

• TDEE calculator
  Find your maintenance calories before cutting.
• Macro calculator
  Split your deficit calories into macros.
• Protein calculator
  Keep protein high to protect muscle in a deficit.
• Meal plan generator
  Build meals that fit your calorie target.