How to use the Weight Loss Percentage Calculator
- Enter the starting weight.
- Enter the current weight in the same unit.
- Read the percentage lost (or gained) and the difference.
How weight loss percentage is calculated
Subtract the current weight from the starting weight, divide by the starting weight and multiply by 100. From 200 lb to 184 lb: (200 − 184) ÷ 200 × 100 = 8%.
Why use a percentage?
A percentage makes progress comparable between people of different sizes, which is why weight-loss challenges and studies often report it instead of pounds or kilograms. Doctors also use percentage change to track weight over time, for example after an illness or when a medicine affects appetite.
Units don't matter
Because it's a ratio, the result is the same in pounds, kilograms or stones. Just use the same unit for both weights. For stones and pounds, convert to pounds first (1 stone = 14 lb).
Weight naturally changes by a kilogram or two over a day, so compare weights taken at the same time of day. For advice about a healthy weight for you, talk to a doctor.
Frequently asked questions
What if my weight went up?
The calculator shows the percentage gained instead.
Is my data stored?
No. The calculation runs in your browser, and nothing is saved or sent anywhere.
Is it free?
Yes, free with no sign-up. Everything is calculated in your browser.