Weight Loss Percentage Calculator
Dropping from 200 lb to 175 lb means 25 lb lost, which is a 12.5% change from your starting weight. This weight loss percentage calculator compares your starting and current weight to show how much weight was lost and what share of the starting weight that change represents.
Quick answer
Weight loss percentage is weight lost divided by starting weight, shown as a percent.
Use the same unit for both entries and, if possible, compare weigh-ins taken under similar conditions.
What this tells you
- •Weight loss percentage is weight lost divided by starting weight, shown as a percent.
- •The result depends only on the two scale values you enter.
- •It does not show whether the change was body fat, water, muscle, or an intended health outcome.
How to Use
- 1Enter your starting weight from the beginning of the period you want to compare.
- 2Enter your current weight using the same unit and, if possible, similar weigh-in conditions.
- 3Choose pounds or kilograms, then calculate.
- 4Review the percentage lost together with the amount lost in pounds and kilograms.
- 5If your current weight is above your starting weight, use a general weight change tool instead of a weight loss percentage result.
How It Works
Formula
Weight lost = starting weight - current weight
Weight loss percentage = (weight lost / starting weight) x 100
Current weight as % of start = (current weight / starting weight) x 100The calculator subtracts your current weight from your starting weight to find the amount lost. It then divides that amount by the starting weight to show the share of body weight that changed over the comparison period. Because the percentage uses the starting weight as the baseline, the same number of pounds or kilograms lost can mean different percentages for different people.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Example in pounds
Losing 25 lb from a 200 lb starting point means 25 divided by 200, or 12.5%.
Example in kilograms
The scale change is 7.5 kg. Dividing 7.5 by 92 gives about 0.0815, or 8.15%.
Common mistakes
- Entering starting and current weight in different units
- Reversing the weights so the current value is higher than the starting value
- Treating short-term water changes as the same thing as body fat loss
- Comparing weigh-ins taken under very different conditions, such as morning versus evening
Limitations
This calculator compares two scale weights only. It does not adjust for hydration, glycogen, clothing, scale error, pregnancy, edema, body-fat percentage, or lean-mass changes. A percentage alone cannot show whether the change was intended, healthy, or clinically significant.