Weight change calculator
Weight loss percentage calculator
Compare a starting and current measurement in pounds or kilograms. See the percentage change, with increases and decreases clearly labeled.
Published by The GLP-1 Verdict. October 2026.
Your two measurements
Use the same unit for both weights. Switching units converts any valid numbers you have entered.
Results update as you type. Your entries are not saved, added to the URL or sent by this calculator.
Percentage change
Enter a positive starting and current weight to see the change. The result describes your measurements; it does not judge them or predict future weight.
What different percentages mean in numbers
These 5–25% reductions are arithmetic reference points from your starting weight. They are not recommended goals, treatment targets or predictions of a medicine’s effects.
Enter a valid starting weight to see the reference points.
The calculation
Percentage reduction = (starting weight − current weight) ÷ starting weight × 100. A change from 100 kg to 90 kg is 10%; a change from 100 kg to 110 kg is a 10% increase.
A measurement, not a forecast
This tool does not use medication, dose, treatment duration or clinical history. Its reference points explain percentages only. They do not indicate what you should weigh or what a medicine will do.
Percentage questions
- How do you calculate weight loss percentage?
- Subtract the current measurement from the starting measurement, divide by the starting measurement, then multiply by 100. For example, a change from 200 lb to 180 lb is (200 − 180) ÷ 200 × 100 = 10%. The starting weight is the denominator.
- Does the percentage change if I use kilograms instead of pounds?
- No, provided both measurements use the same unit and represent the same weights. The units cancel in the percentage formula. The calculator converts both valid entries when you switch units; displayed conversions are rounded, so very small rounding differences can occur.
- What if my current weight is higher than my starting weight?
- The formula returns a negative reduction percentage. This calculator labels that result as an increase and shows its magnitude, rather than presenting it as weight loss. Equal measurements produce 0% change. Both measurements must be positive numbers.
- Are the 5–25% reference points goals or GLP-1 predictions?
- No. They are arithmetic examples based only on the starting measurement you enter. The calculator does not recommend a target, estimate a treatment outcome or determine whether a weight change is appropriate. Those decisions need individual clinical context.