Weight Loss Percentage Calculator: How Much of Your Body Weight Have You Lost?

Weight loss percentage uses one formula:

Worked Example in Pounds

Worked Example in Kilograms

The unit does not matter as long as both weights use the same one. If your current weight is higher than your starting weight, the same formula gives a negative number, and the calculator reports it as a percentage gained.

Percent Lost vs. Percent of a Goal Completed

These are different numbers. Percent lost compares the change to where you started, which is how clinical studies report results. Percent of a goal completed compares the change to a target you chose. A 20 lb loss from 250 lb is 8% lost, whatever the goal was. This calculator reports percent lost only.

The clinical benchmarks are percentages, not pounds, because the health effects of weight loss scale with starting weight. The research lines up around three markers.

The 5% marker comes largely from Look AHEAD (Wing et al., Diabetes Care, 2011), which followed 5,145 adults with type 2 diabetes. Compared with people whose weight stayed stable, those who lost 5 to under 10% had significantly higher odds of a 0.5 point drop in HbA1c, a 5 mmHg drop in blood pressure, and improvements in HDL cholesterol and triglycerides. The odds were greater still at 10 to 15%.

A review by Ryan and Yockey (Current Obesity Reports, 2017) laid out the gradient: modest loss of 5 to 10% is associated with improvements in blood pressure and HDL cholesterol; conditions such as obstructive sleep apnea and nonalcoholic steatohepatitis need 10 to 15%; and quality of life, mobility, and several other measures keep improving as loss increases. The National Institute of Diabetes and Digestive and Kidney Diseases uses the same 5 to 10% benchmark.

Multiply your starting weight by the percentage. The table shows common starting weights; the calculator above does it for yours.

A steady pace makes these numbers easier to keep. The Centers for Disease Control and Prevention notes that people who lose weight gradually, about 1 to 2 pounds a week, are more likely to keep it off than people who lose it faster.

Clinical trials of weight-loss medications report results as percent of body weight lost, which is why this is the number people compare. The two landmark trials of the FDA-approved brand-name GLP-1 medications reported these averages. They are trial results, not predictions of what any one person will lose.

Semaglutide: STEP-1, 68 Weeks

Adults taking semaglutide lost an average of 14.9% of body weight over 68 weeks, versus 2.4% on placebo. 86.4% lost 5% or more, 69.1% lost 10% or more, and 50.5% lost 15% or more (Wilding et al., New England Journal of Medicine, 2021).

Tirzepatide: SURMOUNT-1, 72 Weeks

Adults taking tirzepatide lost an average of 15.0% to 20.9% of body weight over 72 weeks depending on the dose studied, versus 3.1% on placebo. At the two higher doses, 50% and 57% lost 20% or more (Jastreboff et al., New England Journal of Medicine, 2022).

Both trials enrolled adults with a BMI of 30 or higher, or 27 or higher with a weight-related condition, and both paired the medication with a reduced-calorie diet and increased physical activity. Individual results varied widely. These results come from trials of the FDA-approved brand-name products. Protocol MD's semaglutide and tirzepatide are compounded. Compounded medications are not FDA-approved, are not generic equivalents of, and are not the same product as, the brand-name medications studied in these trials.

To see those published averages applied to your own weight as a range, use the GLP-1 weight loss calculator.

Twenty pounds means something different at 160 lb than at 320 lb. At 160 it is 12.5% of body weight; at 320 it is 6.3%. Percentages put everyone on the same scale, which is why physicians and clinical trials use them and why the health benchmarks above are written as percentages rather than pounds.

Percentage also keeps progress honest over time. Early losses on any program are partly water, and later losses come more slowly, so tracking percent lost against your original starting weight, rather than against last week, shows the real direction.

Weight loss percentage tells you how much the scale has moved. It does not tell you what moved. A loss can be fat, muscle, or water, and during larger losses some of it is always lean mass. That is why protein intake and resistance training matter while you lose weight; the protein calculator (grams per day and per meal) estimates a daily range for your goal.

BMI describes where your weight sits for your height, and the BMI calculator, with its limitations spelled out shows it with its limits spelled out. Waist size and body fat percentage say more about where weight is carried. Used together, these measures give a fuller picture than any one of them.

Protocol MD is a physician-guided telehealth practice. A percentage is a way to measure change, not a treatment plan, and whether any medication is appropriate for you depends on your history, your labs, and your goals. Only a licensed physician can make that call after reviewing them.

For patients a physician determines are appropriate candidates, Protocol MD prescribes compounded semaglutide or tirzepatide. Compounded medications are not FDA-approved, and the trial results on this page come from the brand-name products, not from compounded preparations.