Calorie Deficit Projection
Project your cumulative calorie deficit and expected weight change over weeks based on your TDEE and daily calorie intake. Includes a week-by-week chart.
How to use this tool
- Enter daily calorie needs (tdee), daily calorie intake and projection weeks in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your weekly deficit and the full breakdown beneath it.
Tracking your cumulative calorie deficit over time helps you see whether you are on track for your weight-loss goal. The 3,500 kcal per pound rule gives a rough projection of expected weight change.
Metabolic adaptation, water retention and individual variation mean actual results will differ. Not medical advice.
⚠ This tool is for general information and education only and is not medical advice. Consult a qualified healthcare professional before making health decisions.
Formula
Daily deficit (kcal) = TDEE − daily intake
Weekly deficit (kcal) = daily deficit × 7
Total deficit (kcal) = daily deficit × 7 × weeks
Projected weight change (lb) = total deficit ÷ 3,500
How it works
This tool projects cumulative calorie deficit and the implied weight change using the widely cited rule that approximately 3,500 kcal of deficit corresponds to one pound of body fat. It models intake and TDEE as fixed over the projection period, producing a linear trend. In practice, metabolic adaptation, changes in body composition, and adherence variation mean actual weight loss is often somewhat less than projected; nonetheless the model provides a useful planning baseline for short-to-medium-term goals.
Worked example
- TDEE = 2,200 kcal/day, intake = 1,700 kcal/day. Daily deficit = 2,200 − 1,700 = 500 kcal.
- Weekly deficit = 500 × 7 = 3,500 kcal.
- Projection = 4 weeks. Total deficit = 3,500 × 4 = 14,000 kcal.
- Projected weight change = 14,000 ÷ 3,500 = 4.0 lb.
Weekly deficit 3,500 kcal; total deficit 14,000 kcal; projected loss 4.0 lb over 4 weeks.
Common mistakes to avoid
- Using a TDEE calculated at current weight without updating it as weight drops — TDEE decreases with mass, so the actual weekly deficit shrinks and the projection becomes increasingly optimistic.
- Assuming a 500 kcal/day deficit always equals exactly 1 lb/week — metabolic adaptation and lean-mass changes mean real weight loss slows after the first few weeks.
- Entering total daily calories that already include exercise calories added on top of a non-sedentary TDEE, effectively double-counting activity and understating the deficit.
Key terms
- TDEE (Total Daily Energy Expenditure)
- The total number of calories a person burns in a day, combining basal metabolic rate with the thermic effect of food and all physical activity.
- Calorie deficit
- A state where energy intake is below energy expenditure, causing the body to draw on stored fat (and some muscle) for fuel.
- 3,500 kcal per pound rule
- A longstanding approximation stating that a cumulative deficit of 3,500 kcal equates to roughly one pound of fat loss; it oversimplifies metabolic adaptation but is useful for rough planning.
- Metabolic adaptation
- The body's tendency to reduce TDEE in response to sustained calorie restriction, meaning the actual rate of weight loss slows compared to a static-model projection.
- Calorie surplus
- A state where intake exceeds TDEE; entering a negative deficit value in this tool will project weight gain rather than loss.
Frequently asked questions
- What is TDEE?
- Total Daily Energy Expenditure — the total calories you burn per day including exercise and daily activity. Use a TDEE calculator if you don't know your number.
- Can I also project a surplus (muscle gain)?
- Yes — enter an intake higher than your TDEE. The deficit will be negative, representing a surplus, and weight change will be positive.