Calorie deficit calculator
HealthEstimate how many days, weeks and months it takes to reach your goal weight with a given daily deficit.
Your results
Estimate the time needed to reach your goal weight.
How the timeline is estimated
We assume roughly 7700 kcal of deficit per kilogram of body fat. The total deficit per day is multiplied to estimate the number of days to reach the goal weight.
Is the estimate accurate?
Real weight loss is rarely linear because of water retention, plateaus and metabolic adaptation. Use this as a planning estimate, not an exact prediction.
Frequently asked questions
Answers to the most common questions about this tool.
How is this result calculated?
It uses the method and inputs described on this page to provide an informational estimate.
How accurate is the result?
It is an estimate and should be interpreted as a guide, not an exact measurement.
When should I seek professional advice?
Seek qualified advice for symptoms, pregnancy, illness, medication use, or clinical decisions.
What information do I need to enter?
Enter current, accurate details and select the correct units before calculating.
What can affect this estimate?
Individual factors such as health, activity, body composition, and measurement technique can affect it.
Sources and methodology
Methodology: Estimated deficit timeline
Multiplies weight to lose by 7700 kcal and divides by the entered daily deficit.
It is a simplification; real weight loss is not linear.
Last reviewed
July 15, 2026