Project how long reaching a goal weight takes. A pound of fat is about 3,500 calories, so a daily deficit drives a weekly loss — and the weeks to goal follow from the pounds to lose.
The example
20 lb to lose, 500 cal/day deficit.
| A | B | |
|---|---|---|
| 1 | Item | Value |
| 2 | Weekly loss | 1 lb |
| 3 | 20 ÷ 1 | → 20 weeks |
The formula
The formula:
How it works
How it works:
- A pound of body fat is roughly 3,500 calories — the classic rule of thumb.
- Weekly loss =
daily_deficit × 7 / 3500— a 500/day deficit is ~1 lb/week. - Divide pounds to lose by weekly loss for the weeks to goal.
- It’s a linear estimate — real loss slows as you go and metabolism adapts.
Educational use only. These are general Excel formulas for learning spreadsheet techniques — estimates only, not training, medical, or nutrition advice. Individual results vary; consult a qualified professional before acting on them.
Try it: interactive demo
Pounds to lose and daily deficit.
Variations
Weekly loss
From the deficit:
Deficit for a target date
Solve backwards:
Goal date
From today:
Pitfalls & errors
Linear estimate. Real loss slows over time as metabolism adapts.
Safe deficits. Very large deficits aren’t healthy or sustainable.
Educational only. Not a diet plan — consult a professional.
Practice workbook
Frequently asked questions
How do I project a weight-loss timeline in Excel?
How many calories is a pound of fat?
What deficit hits a target date?
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