Weight Loss Time Estimator
Estimate how long it could take to reach a weight target using the widely cited 3,500-calorie-per-pound rule. Enter your goal in pounds and the average daily calorie deficit from diet and exercise to see an approximate timeline.
For educational planning only—seek personalised advice from a registered dietitian or physician before starting a weight-loss program.
Examples
- 10 lb goal with a 500 calorie deficit ⇒ 70.00 days
- 5 lb goal with a 750 calorie deficit ⇒ 23.33 days
- 15 lb goal with a 600 calorie deficit ⇒ 87.50 days
FAQ
Why does the calculator use 3,500 calories per pound?
It is a long-standing rule of thumb derived from the estimated energy content of adipose tissue, though modern research suggests individual variation.
Can I enter goals in kilograms instead of pounds?
Convert kilograms to pounds by multiplying by 2.20462 before using the calculator to keep the formula accurate.
What happens if my calorie deficit changes day to day?
Use an average daily deficit over a week or rerun the calculator with different scenarios to reflect lifestyle changes.
Does the result guarantee fat loss?
No. Hormones, sleep, stress, and activity levels influence progress, so treat the figure as an approximate planning tool.
Is there a maximum recommended deficit?
Healthcare professionals often caution against deficits greater than 1,000 calories per day unless medically supervised.
Additional Information
- Assumes a linear relationship where 3,500 calories correspond to one pound (0.45 kg) of body fat.
- Healthy plans often limit weekly loss to 1–2 lb; divide the result by 7 to estimate the number of weeks required.
- Deficits above 1,000 calories per day may be unsustainable or unsafe without medical supervision.
- Metabolic adaptation, water retention, and body composition changes can cause actual timelines to differ.