Weight Loss Calculator: How Long Will It Really Take?
A target weight feels vague until you turn it into weeks and a daily deficit. This calculator does that simple maths for you.
What is the Weight Loss Calculator?
This tool takes the gap between your current and target weight and divides it by your planned weekly loss rate to estimate the number of weeks needed. It also converts that rate into a daily calorie deficit, using the rough rule that one kilogram of body fat stores about 7,700 calories. The result is general information only, not medical advice, and real loss is rarely perfectly steady week to week.
How to use it
- Enter your current weight and your target weight.
- Enter how many kilograms per week you aim to lose.
- Read the estimated weeks and the daily calorie deficit.
Worked example
Going from 90 kg to 80 kg at 0.5 kg per week takes 20 weeks, with a daily calorie deficit of 550 calories (0.5 × 7,700 ÷ 7).
How long does it take to lose 10 kg?
At 0.5 kg per week, losing 10 kg takes about 20 weeks, or roughly five months, with a daily deficit of around 550 calories. At 1 kg per week it would take about 10 weeks, but that faster pace is tougher to hold and leaves less room for error. A slower, steadier plan you can actually keep usually beats a fast one you abandon.
Frequently asked questions
What is a safe weekly rate?
A commonly suggested pace is around 0.5 kg per week; faster rates are harder to sustain and more likely to cost muscle as well as fat.
Why is the deficit only an estimate?
The 7,700-calories-per-kilogram rule is an average, and your body's burn changes as you lose weight, so treat the timeline as a guide.