Calorie Deficit Calculator for Weight Loss
Enter your maintenance calories and how fast you want to lose weight to get a daily calorie target.
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Formula
Daily deficit = weekly loss (kg) x 7700 / 7Daily target = maintenance calories - daily deficitWeeks to goal = weight to lose / weekly loss
Worked example
Maintenance 2500 kcal, lose 10 kg at 0.5 kg a week: deficit = 0.5 x 7700 / 7 = 550 kcal, target = 2500 - 550 = 1950 kcal, and 10 / 0.5 = 20 weeks.
Frequently asked questions
How big a calorie deficit do I need?
A common rule of thumb is that 1 kg of body fat holds about 7700 kcal. To lose 0.5 kg a week you need roughly 0.5 x 7700 / 7 = 550 kcal less per day.
What is a safe rate of weight loss?
Many health bodies suggest about 0.25 to 1 kg a week. Faster loss is harder to sustain and can cost muscle. This calculator refuses targets under 800 kcal a day.
How do I find my maintenance calories?
Maintenance is the energy you burn in a day. Estimate it from a TDEE calculator, or track your intake and weight for two to three weeks while weight stays steady.
Why does weight loss slow down over time?
As you get lighter you burn fewer calories, so the same intake gives a smaller deficit. The 7700 kcal figure is an average, so treat the weeks estimate as a guide.