Diet & fitness
Calorie Deficit Calculator
Enter your goal weight and pick a pace. Get the exact daily deficit, the calories to eat, and a realistic timeline to your goal — free.
Based on the Mifflin-St Jeor equation
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Calorie deficit
Based on the Mifflin-St Jeor equation and roughly 7,700 kcal per kg of body mass. Weight loss isn't perfectly linear; use this as a guide and adjust. General information, not medical advice.
How a calorie deficit works
- 01
Find maintenance
We estimate the calories that hold your weight steady (your TDEE) from the Mifflin-St Jeor equation and your activity level.
- 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.
- 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.