To lose about one pound per week, eat roughly 500 kcal per day below your maintenance calories — that is the arithmetic of the 3,500-kcal-per-pound approximation this calculator uses. Enter your TDEE and a weekly loss target and it returns the daily calorie budget that gets you there, with CDC guidance framing a gradual 1 to 2 lb per week as the sustainable pace.
Suppose you put the default values into Calorie Deficit Calculator:
Plug those into the formula target = TDEE − (loss_lb · 3500 / 7) and the result is:
With the default 2,700 kcal maintenance and a 1 lb per week target, the daily deficit is 3,500 / 7 = 500 kcal, so the eating target is 2,200 kcal per day. Held exactly, that pace works out to about 4.3 lb per month — in practice the rate drifts as maintenance calories fall with weight, which is why re-running the numbers periodically beats setting them once.
| Weekly loss target | Daily deficit |
|---|---|
| 0.5 lb | 250 kcal |
| 1 lb | 500 kcal |
| 1.5 lb | 750 kcal |
| 2 lb | 1,000 kcal |
Derived from the 3,500 kcal/lb approximation
The calculator applies the classic energy-balance approximation: a pound of body fat stores about 3,500 kcal, so a weekly loss target converts to a daily deficit of target x 3,500 / 7, which is subtracted from your maintenance calories (TDEE) to give the eating target. It is deliberately simple — real-world loss is not perfectly linear, because maintenance calories themselves fall as weight falls and early losses include water weight. The CDC's healthy weight loss guidance, the cited reference, emphasizes gradual, steady loss of about 1 to 2 pounds per week over aggressive cuts.
References: CDC: Healthy weight loss.
Last reviewed July 2, 2026 · Editorial policy