Weight Loss and Gain Timeline Calculator
Estimates the time and date to reach a goal weight. Not suitable in pregnancy or for under-18s.
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
The formula
each week: change = daily change × 7 ÷ 7,700 maintenance is recalculated at the new weight
A loss target stops at 1,200 kcal a day for women and 1,500 for men. Once it gets there, the deficit and the weekly loss shrink as weight falls.
What to watch out for
Each week, maintenance is worked out from the Mifflin-St Jeor equation (1990) at your weight that week. A fixed deficit gives a steady loss until the target reaches the calorie floor, and then the loss slows. The calorie floors are the lower end of the intakes in the 2013 AHA/ACC/TOS obesity guideline (Jensen and colleagues). A goal under a BMI of 18.5 is below the WHO healthy range. The body adapts in ways this does not capture (Hall and colleagues, Lancet, 2011), and plateaus are normal, so treat the date as a rough guide.
Frequently Asked Questions
How long does it take to lose 8 kg?
A 35-year-old woman, 168 cm, going from 80 to 72 kg with light activity and a 500 kcal daily deficit: about 18 weeks.
Why does a bigger deficit not always bring the date closer?
The target stops at the calorie floor, so past that point the date stays the same. For that same woman, asking for 1,500 kcal a day gives about 11 weeks, and asking for 3,000 kcal also gives 11.
Why might my progress differ from this?
Early weight changes include water, and everyday movement often falls as you lose weight. Week-to-week swings are normal, so the trend over a month tells you more.