Free Tool
Weight Loss Percentage Calculator
See what percent of your body weight you've lost and project your time to a goal weight. A general estimate for GLP-1 journeys — not medical advice.
Enter your weights, then Calculate.
How much weight do people lose on GLP-1 medications?
Weight-loss percentage is the clearest way to compare progress across different starting weights: someone who starts at 320 lb and someone who starts at 180 lb can both lose "10%" and be on comparable footing. It's also the metric used in the major GLP-1 clinical trials, so it's easy to benchmark against published averages.
In clinical trials, average results were roughly 15% of body weight over about 68 weeks for semaglutide (the STEP program), and about 20–22% of body weight for tirzepatide (the SURMOUNT program), each combined with diet and activity changes. These are trial averages — real outcomes span a wide range, and many people lose more or less than the headline figure.
~5–10%
Often enough to measurably improve blood pressure, blood sugar, and cholesterol for many people.
~15%
Average body-weight reduction with semaglutide over ~68 weeks in the STEP trials.
~20–22%
Average body-weight reduction with tirzepatide in the SURMOUNT trials.
Clinical-trial averages are shown for context only. They are not a prediction of your results, not a guarantee, and not medical advice. Individual results vary widely based on dose, duration, lifestyle, and individual biology. Any medication decision should be made with your prescriber.
Related tools: BMI Calculator · GLP-1 Dose Calculator · All tools
Frequently asked questions
How do I calculate my weight loss percentage?
Subtract your current weight from your starting weight, divide by your starting weight, and multiply by 100. For example, going from 200 to 180 lb is (200 − 180) ÷ 200 × 100 = 10% of body weight lost. This calculator does the math for you in either pounds or kilograms.
What is a good weight loss percentage on GLP-1 medications?
In clinical trials, average results were roughly 15% of body weight over about 68 weeks for semaglutide (STEP trials) and about 20–22% for tirzepatide (SURMOUNT trials). These are trial averages — your individual results will vary, and you should follow your prescriber's guidance.
How much weight will I lose on semaglutide?
No tool can predict your exact result. In the STEP trials, adults on semaglutide lost an average of about 15% of their body weight over roughly 68 weeks alongside lifestyle changes. Use this as a general reference, not a guarantee, and discuss realistic expectations with your clinician.
How long will it take to reach my goal weight?
If you enter a goal weight and an average weekly loss rate, this calculator divides the remaining weight by your weekly pace to estimate the number of weeks and a projected goal date. Weekly loss is rarely perfectly steady, so treat the date as an estimate rather than a fixed deadline.
Is losing 5% of my body weight meaningful?
Yes — research consistently shows that losing 5–10% of body weight can produce measurable improvements in blood pressure, blood sugar, and cholesterol for many people. Even modest percentages matter, but any treatment decision should be made with your clinician.
Does this calculator give medical advice?
No. This is a general estimate tool for context and motivation, not medical advice, a diagnosis, or a treatment recommendation. Always follow your prescriber's and clinician's guidance for any weight-management plan or medication.
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