The most common diet question is not “how” — it is “how long will this take?” This calculator does honest maths: it works out your daily calorie needs, applies a steady pace of change, and gives you the date you can realistically expect to reach your target weight.
Weight Goal Date Calculator
Estimate only — not medical advice.
How the Weight Goal Date Calculator Works
The calculator first finds your maintenance calories (your TDEE, from the Mifflin-St Jeor equation × your activity level). To lose weight you eat below that by your chosen pace; to gain, above it. The timeline uses the standard estimate that 1 kg of body fat stores about 7,700 kcal: total change needed (kg × 7,700) ÷ daily deficit or surplus = days to your goal.
Worked Example
A 30-year-old man, 80 kg, 178 cm, moderately active (TDEE ≈ 2,740 kcal), targeting 75 kg at a 500 kcal/day deficit: 5 kg × 7,700 = 38,500 kcal ÷ 500 = 77 days — about 11 weeks, eating roughly 2,240 kcal/day (his TDEE goal calories on the “Lose weight” setting).
Read This Before You Trust the Date
- Real weight loss is not a straight line. Water shifts hide fat loss for days, then release it in a “whoosh”. Judge by 2-week averages, not single mornings.
- The pace slows as you get lighter — a lighter body burns fewer calories, so later kilos take slightly longer than the estimate.
- Never eat below 1,200 kcal/day (this calculator refuses paces that would take you there) — very low intakes risk muscle loss, nutrient gaps and rebound binging.
- Recheck your date every 5 kg with the TDEE Calculator and adjust.
Frequently Asked Questions
How long will it take to lose 10 kg?
At a steady 0.5 kg per week, about 20 weeks — roughly 5 months. Faster paces exist, but slower ones keep far more of the weight off after year one.
Why does the calculator block very fast paces?
If your chosen deficit would push your daily food below 1,200 kcal, the pace is unsafe for almost everyone. The calculator asks you to pick a slower pace instead.
Is 7,700 kcal per kg exact?
It is the accepted average for body fat (about 3,500 kcal per pound). Real bodies vary a little, and early diet weeks include water loss, so treat the date as a realistic estimate — usually within a couple of weeks.
Does this work for gaining muscle too?
Yes — choose a target above your current weight and a modest pace (0.25 kg/week is plenty for muscle). Beyond that rate, extra gain is mostly fat.