Average weight loss on a GLP-1, mapped to your weight.

Answer a few questions and find out how much weight you could lose and how quickly.

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Which GLP-1 medication are you on, or thinking about?

This is an educational estimate. Figures are population means from randomized trials and will differ for any individual based on dose, adherence, diet, activity, and physiology. It is not a prediction, a guarantee, or medical advice. Talk to a licensed clinician before starting or changing any medication.

The same tool for other medications: Ozempic weight loss calculator, Wegovy weight loss calculator, Semaglutide weight loss calculator, Mounjaro weight loss calculator, Zepbound weight loss calculator, and Tirzepatide weight loss calculator.

Sources: STEP-1 ↗ · SURMOUNT-1 ↗

Compare these medications Browse weight loss doctors Read the research

How the GLP-1 weight loss calculator works

Trial-anchoredSTEP-1 · SURMOUNT-1Estimate, not medical advice

Medically reviewed by Dr. Fahad Akhtar, M.D.

Physician at g1v.me, an affiliated practice

Updated October 4, 2026

Enter your weight and height, then pick a medication and dose. The tool takes the average weight loss measured in that drug's main clinical trial: STEP-1 for semaglutide, SURMOUNT-1 for tirzepatide. It maps that trial figure onto your starting weight, plotting your projected weight and BMI week by week. The numbers come straight from the published trials, not a generic calorie formula.

Percent of body weight lost by week on Zepbound 15 mg. Dose steps from the FDA label: 2.5 mg to start, 5 mg after 4 weeks, 7.5 mg after 8 weeks, 10 mg after 12 weeks, 12.5 mg after 16 weeks, then 15 mg after 20 weeks. Those are the label's weeks for each step. Your prescriber sets the pace. The trial measured people at week 72 (SURMOUNT-1). The curve before it is our estimate. Loss is fastest early and flattens by about month 17. Source: SURMOUNT-1 ↗

What SURMOUNT-1 found

SURMOUNT-1 gave 2,539 adults with obesity, or overweight with a weight-related condition, and no diabetes, weekly tirzepatide or placebo for 72 weeks. Mean weight change was −15.0% on 5 mg, −19.5% on 10 mg, and −20.9% on 15 mg, against −3.1% on placebo. The first 20 weeks were dose escalation.

Group	Mean weight change, week 72	Lost 5% or more
Tirzepatide 5 mg	−15.0%	85%
Tirzepatide 10 mg	−19.5%	89%
Tirzepatide 15 mg	−20.9%	91%
Placebo	−3.1%	35%

Trial means, not a prediction for any one person. Sources: SURMOUNT-1 on PubMed · Zepbound FDA label

What STEP-1 found

STEP-1 gave 1,961 adults with obesity, or overweight with a weight-related condition, and no diabetes, weekly semaglutide 2.4 mg or placebo for 68 weeks, with lifestyle support. Mean weight change was −14.9% against −2.4% on placebo, or −15.3 kg against −2.6 kg.

Group	Mean weight change, week 68	Lost 5% or more
Semaglutide 2.4 mg	−14.9%	86.4%
Placebo	−2.4%	31.5%

Trial means, not a prediction for any one person. Sources: STEP-1 on PubMed · Wegovy FDA label

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