How Long to Lose 100 Pounds?
Losing 100 pounds with a 1,000-calorie daily deficit takes approximately 100 weeks under the 3,500-calorie-per-pound rule.
How to use this tool
- Enter current weight, goal weight and daily calorie deficit in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your weeks to goal and the full breakdown beneath it.
A 100-pound weight loss journey is life-changing — map out the full timeline based on a safe, medically-common 1,000-calorie daily deficit.
Frequently asked questions
- Why 3,500 calories per pound?
- The 3,500 kcal/lb rule is a widely used approximation. Actual results vary with age, sex, body composition and metabolic adaptation.
- Is 500 kcal/day a safe deficit?
- A 500 kcal/day deficit targets ~1 lb/week loss and is generally considered safe for most adults, but consult your doctor if you have health conditions.