Free tool
Weight loss percentage calculator
Kilograms lost is the number people quote. Percentage lost is the one that means something, because 5 kg is a very different achievement at 60 kg than at 120. Enter where you started and where you are now.
Updated
The formula
Weight loss % = (starting weight − current weight) ÷ starting weight × 100
From 85 kg to 79 kg is 6 kg lost, and 6 ÷ 85 × 100 = 7.1%.
Use a weekly average for the current weight rather than one morning's reading. A single weigh-in can be a kilogram off in either direction for reasons that have nothing to do with fat. Why your weight fluctuates →
What it means
Why percentage beats kilograms.
Clinical research on weight loss almost always reports percentage lost, not kilograms, because it is comparable between people of different sizes and tracks health outcomes more closely.
The milestones below are where the evidence consistently shows benefit for people who started above a healthy weight. None of them requires reaching a “normal” BMI.
| Loss | What typically changes |
|---|---|
| 3–5% | Measurable improvements in blood sugar and triglycerides begin |
| 5–10% | Blood pressure, blood sugar and cholesterol improve meaningfully; joint load drops noticeably |
| 10–15% | Larger improvements in blood sugar control; sleep apnoea often improves |
| 15%+ | Type 2 diabetes remission becomes realistic for many people with a recent diagnosis |
What is a good weight loss percentage per week?
Around 0.5–1% of body weight per week is the range most guidance settles on. It is fast enough to see progress within a month and slow enough that most of the loss is fat rather than muscle.
| Starting weight | 0.5% per week | 1% per week |
|---|---|---|
| 60 kg | 0.3 kg | 0.6 kg |
| 75 kg | 0.375 kg | 0.75 kg |
| 90 kg | 0.45 kg | 0.9 kg |
| 110 kg | 0.55 kg | 1.1 kg |
Expect the first two weeks to run well ahead of this. Cutting back on food and carbohydrates releases stored glycogen and the water bound to it (often 1–2 kg), which shows up as a fast start that does not continue. Weeks three to eight are the honest measure. How much weight you can lose in a month →
Frequently asked questions
How do I calculate weight loss percentage?
Subtract your current weight from your starting weight, divide by your starting weight, and multiply by 100. Losing 8 kg from 100 kg is 8%; losing 8 kg from 80 kg is 10%.
Is 5% weight loss significant?
Yes. For someone who started above a healthy weight, 5% is the point at which improvements in blood pressure, blood sugar and cholesterol become clinically measurable. It is a much more meaningful milestone than it sounds.
Should I use my heaviest weight as the starting weight?
Use your weight at the start of this attempt, averaged over a few mornings if you can. Starting from a heaviest-ever reading inflates the percentage and makes the progress harder to compare over time.
Why has my percentage stopped moving?
A stall of one to two weeks is almost always water. Three weeks or more usually means intake has drifted up or activity has drifted down. See why you are not losing weight in a calorie deficit.
Nothing is stored, is it?
Nothing. The arithmetic runs in your browser and no values are sent anywhere or saved.
Next step
Track the trend, not the morning.
BetterCal syncs your weight from Apple Health or Health Connect and shows the trend alongside what you ate. Free to start on iPhone and Android.
