GLP-1 Weight Loss Calculator
Estimate how much weight you might lose on semaglutide (Ozempic, Wegovy) or tirzepatide (Mounjaro, Zepbound) over the next few months. The estimate uses average results from the large clinical trials behind these medications, shown as a range because individual results vary widely.
How this estimate works
The calculator starts from the average total weight loss reported in the pivotal trial for your medication. In the STEP 1 trial, people taking semaglutide lost an average of about 14.9 percent of their body weight over 68 weeks. In the SURMOUNT-1 trial, people taking the highest dose of tirzepatide lost an average of about 20.9 percent of their body weight over 72 weeks.
For the number of months you choose, the calculator takes the matching share of that trial average. For example, asking about half the trial length gives roughly half the trial average. This is a deliberately simple, linear model. Real weight loss is not perfectly even, since many people lose faster in the earlier months and slower later, with plateaus in between.
Because people respond very differently, the result is shown as a band around the average rather than a single figure. The low end assumes you lose at about 70 percent of the average rate, and the high end assumes about 115 percent of the average rate. Plenty of people fall outside even that band, in both directions.
Frequently asked questions
How accurate is this GLP-1 weight loss calculator?
It is a rough planning estimate, not a prediction. It takes the average weight loss seen in large clinical trials and spreads it evenly over the months you choose. Your own result can be well above or below the average, which is why the result is shown as a range.
Why does the calculator show a range instead of one number?
People respond very differently to GLP-1 medication. In the trials, some people lost much more than the average and some lost much less. A range built around the published average is more honest than a single number.
What if I lose weight faster or slower than the estimate?
That is common and usually not a reason to worry on its own. Weight loss on GLP-1 medication often comes in phases, with plateaus along the way. If you are concerned about your progress, talk to the doctor who prescribed your medication.