Calorie Deficit Calculator
Choose how fast you want to lose, get the daily calories that make it happen and, if you set a goal weight, the number of weeks it should take.
Want to turn these numbers into a plan you will actually follow?
A coach adjusts the calories and macros to your real life, your training and your progress. Compare weight loss and body transformation coaches on BoulderGain.
Continue with
Example
Maintenance 2,600 kcal, goal 1 lb per week: target 2,100 kcal a day. From 200 lb to 180 lb that is about 20 weeks.
Method and formula
A deficit of 3,500 kcal is roughly 1 lb of fat (7,700 kcal per kg). The daily deficit = weekly loss × 7,700 / 7 (in kg).
The target never goes below 1,200 kcal (women) or 1,500 kcal (men), and the calculator flags deficits above 25 % of maintenance.
Limits
- Weight loss is not linear: water and glycogen swings of 2 to 4 lb are normal in the first weeks.
- Very fast rates cost muscle and are hard to hold; 0.5 to 1 % of body weight per week is the usual recommendation.
- Not intended for people under 18.
FAQ
What is a safe calorie deficit?
300 to 500 kcal a day for most people, up to 750 for heavier individuals. Above 25 % of maintenance usually backfires.
Why did I stop losing weight?
Maintenance drops as you get lighter, logging drifts, and daily activity often falls in a deficit. Recalculate and add steps before cutting more food.
Should I do cardio to create the deficit?
Cardio helps, but the deficit is easier to control through food. Keep strength training to protect muscle.
Free educational tool. Body composition, calorie and heart rate values are estimates from published formulas, not medical measurements. They do not replace a professional assessment. No weight-loss recommendation is intended for people under 18.