What This Calculator Does
The Weekly Weight Loss Calculator tells you the daily calorie deficit you need to maintain in order to lose a chosen number of pounds each week. It is based on the widely used estimate that one pound of body fat is equivalent to about 3,500 calories of stored energy. While individual results vary, this rule of thumb is a practical starting point for planning a diet and exercise routine.
How to Use It
Enter your target weight loss per week in pounds — most experts recommend a safe, sustainable rate of 1 to 2 lbs per week. Optionally, enter your daily maintenance calories (the amount you burn each day at your current weight). The calculator returns the daily deficit required and, if you provided maintenance calories, your suggested daily intake to hit that goal.
The Formula Explained
The math is straightforward. To lose X pounds in one week you need a weekly deficit of X × 3,500 calories. Spread evenly across 7 days, the daily deficit is:
$$\text{Daily Deficit} = \frac{\text{Loss (lbs/week)} \times 3500}{7}$$Your target intake is simply your maintenance calories minus this daily deficit.
Worked Example
Suppose you want to lose 1.5 lbs per week with a maintenance level of 2,200 calories per day. The weekly deficit is \(1.5 \times 3500 = 5250\) calories. Dividing by 7 gives a daily deficit of 750 calories. Your target daily intake is \(2200 - 750 = 1450\) calories.
FAQ
Is 3,500 calories per pound exact? No. It is an approximation. Real fat loss depends on metabolism, water balance, muscle mass and hormones, so treat the result as a guide.
How fast should I lose weight? Most health authorities suggest 1 to 2 lbs per week. Faster rates can be hard to sustain and may cost muscle.
Should I eat below 1,200 calories? Very low intakes can be unsafe. If your target intake drops too low, choose a smaller weekly goal or add exercise to widen the deficit. Consult a professional before starting any diet.
