Pounds lost is the number everyone reports, and it is the least useful one. Ten pounds is 6.7% of a 150 lb body and 3.3% of a 300 lb body. The health research does not measure success in pounds. It measures it in percent of starting weight, because that is the number that tracks blood pressure, blood sugar and the other changes people actually lose weight for.
This calculator does the division for you, then tells you where the result sits: which clinical milestone you have passed, what you weigh at the next one, how far along you are toward your own goal, and whether your weekly pace is inside the range that protects muscle. If you are on a GLP-1 medication, it also gives you the trial averages to measure yourself against, stated precisely and without any dosing advice.
How this calculator works
The core formula is simple arithmetic. Everything around it comes from a primary source.
- Percent of body weight lost: (starting weight minus current weight) divided by starting weight, times 100. Both weights use the same unit, so the result is identical in pounds or kilograms.
- Milestones: 3 to 5%, 5%, 10%, 15% and 20%. The 3 to 5% band and the 5 to 10% initial goal come from the 2013 AHA/ACC/TOS guideline for managing overweight and obesity (Jensen et al. 2014) in Circulation. The 10 and 15% tiers come from Look AHEAD, analyzed by Wing et al. 2011 in Diabetes Care, and from the review by Ryan and Yockey 2017 in Current Obesity Reports.
- Next milestone: the weight at which you reach the next tier, which is your starting weight times 0.95, 0.90, 0.85 or 0.80, and how much is left to lose to get there.
- Goal progress (optional): the weight you have lost divided by the weight you set out to lose. A goal of 187 lb from 220 lb84.8 kg from 99.8 kg is a 15% goal, and 16 of 33 lb7.3 of 15 kg puts you 48% of the way there.
- Weekly pace (optional): percent lost divided by weeks elapsed, judged against the 0.5 to 1% per week band that Helms, Aragon and Fitschen 2014 recommend in the Journal of the International Society of Sports Nutrition to keep as much muscle as possible.
What 5%, 10% and 15% actually do for your health
The milestone bands are not arbitrary round numbers. Each one lines up with a measured change in health risk.
3 to 5%: where the benefits start
The AHA/ACC/TOS guideline tells clinicians to counsel patients that even a modest, sustained loss of 3 to 5% produces clinically meaningful health benefits, and that greater losses produce greater benefits. It spells out what those first benefits are: lower triglycerides, blood glucose and HbA1c, and a lower risk of developing type 2 diabetes. Blood pressure and cholesterol respond more once the loss gets larger. The guideline also reports that people with type 2 diabetes who lose 2 to 5% are more likely to see a meaningful drop in fasting glucose than people whose weight stays flat.
5 to 10%: the first real goal
The guideline recommends losing 5 to 10% of baseline weight within six months as the initial goal. At a 5% loss it reports average blood pressure reductions of about 3 mm Hg systolic and 2 mm Hg diastolic, and in people with type 2 diabetes a 5 to 10% loss is linked to HbA1c reductions of 0.6 to 1.0 points. Look AHEAD, a trial of 5,145 adults with type 2 diabetes, found that people who lost 5 to under 10% in the first year had 3.5 times the odds of a half-point drop in HbA1c compared with people whose weight held steady, plus better odds of improvements in blood pressure, HDL cholesterol and triglycerides.
10 to 15% and beyond
In the same Look AHEAD analysis, the odds of clinically significant improvement in most risk factors were even greater for people who lost 10 to 15%. Ryan and Yockey's review adds that some conditions need that larger loss before they improve: obstructive sleep apnea and non-alcoholic steatohepatitis typically need 10 to 15%. The review also makes a point worth keeping in mind at any milestone. The target should be a health improvement, not a number on the scale, so a clinician may judge your progress by blood pressure or blood sugar rather than by the percent alone.
Milestone weights for common starting weights
The fastest way to find your own milestones without the calculator: multiply your starting weight by 0.95 for 5%, 0.90 for 10%, 0.85 for 15% and 0.80 for 20%.
| Starting weight | 5% equals | Weight at 5% | At 10% | At 15% | At 20% |
|---|---|---|---|---|---|
| 150 lb70 kg | 7.5 lb3.5 kg | 142.5 lb66.5 kg | 135 lb63 kg | 127.5 lb59.5 kg | 120 lb56 kg |
| 175 lb80 kg | 8.8 lb4 kg | 166.3 lb76 kg | 157.5 lb72 kg | 148.8 lb68 kg | 140 lb64 kg |
| 200 lb90 kg | 10 lb4.5 kg | 190 lb85.5 kg | 180 lb81 kg | 170 lb76.5 kg | 160 lb72 kg |
| 225 lb100 kg | 11.3 lb5 kg | 213.8 lb95 kg | 202.5 lb90 kg | 191.3 lb85 kg | 180 lb80 kg |
| 250 lb110 kg | 12.5 lb5.5 kg | 237.5 lb104.5 kg | 225 lb99 kg | 212.5 lb93.5 kg | 200 lb88 kg |
| 275 lb120 kg | 13.8 lb6 kg | 261.3 lb114 kg | 247.5 lb108 kg | 233.8 lb102 kg | 220 lb96 kg |
| 300 lb130 kg | 15 lb6.5 kg | 285 lb123.5 kg | 270 lb117 kg | 255 lb110.5 kg | 240 lb104 kg |
Worked examples
Seven scenarios run through the calculator with a starting weight, a current weight and the weeks in between, so you can check the tool against your own numbers.
| Start to now | Weeks | Lost | % lost | Weekly pace | Where it lands |
|---|---|---|---|---|---|
| 220 to 204 lb99.8 to 92.5 kg | 12 | 16 lb7.3 kg | 7.3% | 0.61% (1.3 lb0.6 kg) | Past 5%, typical pace |
| 180 to 171 lb81.6 to 77.6 kg | 10 | 9 lb4.1 kg | 5.0% | 0.50% (0.9 lb0.4 kg) | Past 5%, typical pace |
| 150 to 145 lb68 to 65.8 kg | 8 | 5 lb2.3 kg | 3.3% | 0.42% (0.6 lb0.3 kg) | 3 to 5% band, gradual pace |
| 260 to 234 lb117.9 to 106.1 kg | 26 | 26 lb11.8 kg | 10.0% | 0.38% (1 lb0.5 kg) | Past 10%, gradual pace |
| 240 to 204 lb108.9 to 92.5 kg | 52 | 36 lb16.3 kg | 15.0% | 0.29% (0.7 lb0.3 kg) | Past 15%, gradual pace |
| 200 to 186 lb90.7 to 84.4 kg | 6 | 14 lb6.4 kg | 7.0% | 1.17% (2.3 lb1.1 kg) | Past 5%, faster than 1% a week |
| 300 to 240 lb136.1 to 108.9 kg | 68 | 60 lb27.2 kg | 20.0% | 0.29% (0.9 lb0.4 kg) | Past 20%, gradual pace |
Notice the fourth and fifth rows. Losing 10 to 15% over six months to a year works out to under half a percent a week, which is slower than most people expect and still one of the better outcomes on the table.
Losing the weight is one job. Keeping your muscle is the other.
FitCraft, our mobile fitness app, pairs you with a 3D AI coach who builds strength workouts around dumbbells or just your bodyweight, says your name while you train, and keeps you coming back with streaks and leaderboards. Every FitCraft program is designed by Domenic Angelino, MPH (Brown University) and NSCA-CSCS.
Take the Free Assessment Free • 2 minutes • Personalized to youHow fast is too fast? Weekly pace as a percent of body weight
Pace works the same way as the total: percent tells you more than pounds. Two pounds a week is 1% of a 200 lb body and 0.67% of a 300 lb body, so the same number on the scale means a much harder push for the lighter person.
The band the calculator uses comes from Helms and colleagues, who reviewed the evidence on dieting while trying to keep muscle and recommended setting calories so that body weight falls by about 0.5 to 1% a week. The clearest test of why is Garthe et al. 2011. Twenty-four elite athletes lifted four times a week while dieting at either a slow target of 0.7% a week or a fast target of 1.4%. Both groups lost about 5.5% of their body weight. The slow group gained 2.1% lean body mass along the way. The fast group gained none.
A broader review points the same way. Chaston, Dixon and O'Brien 2007 pooled studies of people who lost more than 10 kg and found that the deeper the calorie restriction, the larger the share of weight that came off as fat-free mass. Exercise lowered that share in the three randomized trials that tested it.
Slower than 0.5% a week is not a failure. The guideline reports that comprehensive lifestyle programs average up to 8 kg over six months, which for a 100 kg adult is about 0.3% a week. The long GLP-1 trials averaged a similar pace over their full length. The calculator labels anything between 0.25 and 0.5% a week as gradual, and it treats that as a normal result. Early weeks also tend to run faster than later ones, which is one reason our guide to the weight loss plateau exists.
GLP-1 benchmarks: STEP 1 and SURMOUNT-1
If you take semaglutide or tirzepatide, the fairest comparison is with the trials that led to their approval for weight management. Compare percents, not pounds, and compare at a similar number of weeks. The figures below are trial averages. They are not a prediction for any one person, and nothing on this page is dosing advice. Your prescriber sets and changes your dose.
STEP 1. Wilding et al. 2021 in the New England Journal of Medicine enrolled 1,961 adults with a BMI of 30 or more, or 27 or more with a weight-related condition, and without diabetes. They took once-weekly semaglutide 2.4 mg or placebo for 68 weeks, both groups alongside a lifestyle intervention. Average weight change was minus 14.9% with semaglutide and minus 2.4% with placebo. On semaglutide, 86.4% lost at least 5%, 69.1% at least 10% and 50.5% at least 15%, compared with 31.5%, 12.0% and 4.9% on placebo.
SURMOUNT-1. Jastreboff et al. 2022, also in the New England Journal of Medicine, enrolled 2,539 adults with similar criteria, again without diabetes, and randomized them to once-weekly tirzepatide at 5, 10 or 15 mg or to placebo for 72 weeks, including a 20-week dose-escalation period. Average weight change was minus 15.0%, 19.5% and 20.9% across the three doses, against minus 3.1% on placebo. At least 5% was reached by 85%, 89% and 91% of the three tirzepatide groups and by 35% on placebo. Half of the 10 mg group and 57% of the 15 mg group lost 20% or more.
| Trial group | Length | Average loss | Lost 5% or more | Average weekly pace |
|---|---|---|---|---|
| STEP 1, semaglutide 2.4 mg | 68 weeks | 14.9% | 86.4% | 0.22% |
| STEP 1, placebo | 68 weeks | 2.4% | 31.5% | 0.04% |
| SURMOUNT-1, tirzepatide 5 mg | 72 weeks | 15.0% | 85% | 0.21% |
| SURMOUNT-1, tirzepatide 15 mg | 72 weeks | 20.9% | 91% | 0.29% |
| SURMOUNT-1, placebo | 72 weeks | 3.1% | 35% | 0.04% |
Two things stand out. First, the average weekly pace over each full trial sits well under the 0.5 to 1% band, because weight came off fastest in the early months and leveled off toward the end. Second, the averages hide a real spread. About 1 in 7 people on semaglutide in STEP 1 did not reach 5%. If your percent sits below the trial average at the same week, that is a conversation to have with your prescriber, not a reason to change anything on your own.
A GLP-1 changes how fast the scale moves, but it does not change what the weight is made of on its own. That part depends on what you do alongside the medication. If you want a training app built around that problem, our comparison of the best fitness apps for GLP-1 users ranks the options by how well they help you protect muscle.
Protect lean mass while the number drops
The scale cannot tell fat from muscle. Every percent on this page is total body weight, and some share of it is always lean mass. How big that share gets is the part you can influence.
Cava, Yeat and Mittendorfer 2017, reviewing the evidence in Advances in Nutrition, concluded that diet-induced weight loss reduces muscle mass, that adequate protein helps preserve lean mass, and that resistance exercise both preserves muscle and improves strength. The cleanest trial is Villareal et al. 2017 in the New England Journal of Medicine. In 160 older adults with obesity, every exercise group lost about 9% of body weight. Lean mass fell 5% in the aerobic-only group but only 2 to 3% in the groups that did resistance training, and strength rose 18 to 19% with lifting against 4% with aerobic work alone.
The GLP-1 data fit the same pattern. In the SURMOUNT-1 body composition substudy, Look et al. 2025 scanned 160 participants and found that about 75% of the weight lost on tirzepatide was fat and 25% was lean mass, the same split seen on placebo. A 2024 review of GLP-1 body composition studies by Neeland, Linge and Birkenfeld reported a much wider range across trials, from about 15% or less up to 40 to 60% of weight lost, and noted that lean mass also includes organs, bone and water, so it is not the same thing as muscle.
The practical version is short. Lift two to three times a week, with every major muscle group trained at least twice. Eat enough protein, and use our protein calculator to set a daily target. Keep the weekly pace in or under the 0.5 to 1% band where you can. If you want to lose fat and build muscle at the same time, the body recomposition calculator tells you whether that is realistic for you, and our guide on how to lose fat without losing muscle covers the training side in detail.
Three myths about weight loss numbers
Myth 1: pounds lost is the number that matters
Pounds are what the scale shows, so pounds are what people compare. But the thresholds in the obesity guideline and in the drug trials are all stated as a percent of starting weight. A 15 lb loss is a 10% milestone at 150 lb and a 5% milestone at 300 lb. Comparing your pounds with someone else's tells you almost nothing. Comparing percents does.
Myth 2: faster is always better
A faster loss gets you to a number sooner, and it can cost more lean mass on the way. Garthe et al. 2011 is the clearest example: both groups reached about the same total loss, and only the slower group gained lean mass. Chaston et al. 2007 found the same direction across many studies. Speed is not free, and past about 1% a week the price usually goes up.
Myth 3: weight lost on a GLP-1 is mostly muscle
The SURMOUNT-1 substudy found that about a quarter of the weight lost on tirzepatide was lean mass, which is the same share as the placebo group lost through diet and lifestyle alone. The drug did not change the ratio. It changed the size of the loss, which means more total lean tissue lost unless you train. That is a reason to lift, not a reason to avoid the medication. We cover the full evidence in our review of GLP-1 muscle loss research.
When to ignore this calculator
The calculator is built for adults who are losing weight on purpose. In a few situations a percent is the wrong thing to track, and a clinician is the right next step.
- Eating disorders, now or in the past. Percent targets, milestones and weekly pace can feed restrictive patterns. A clinician or registered dietitian who specializes in eating disorders is the right guide, not a calculator.
- Pregnancy and breastfeeding. Intentional weight loss is not appropriate during pregnancy, and postpartum targets belong with your obstetric care team.
- Rapid or unexplained weight loss. Losing 5% or more of your body weight over 6 to 12 months without trying is how clinicians usually define unintentional weight loss (Gaddey and Holder 2021, American Family Physician, writing about adults over 65), and it needs a medical evaluation at any age. The same applies if intended loss is running far faster than you planned.
- Questions about weight-loss medication. Starting, stopping, changing a dose, side effects, and what to do if progress stalls are all questions for your prescriber. This page reports trial results and gives no dosing advice.
- Under 18. Adolescents are still growing, so percent-of-weight targets do not apply in the same way. Weight management for teens belongs with a pediatric clinician.
- Older adults and anyone with low muscle mass. Weight loss after 65 can cost muscle and bone that are hard to regain. Villareal et al. 2017 shows that exercise, especially with resistance training, protects them, so plan the loss with your clinician.
Related reading
References
- Jensen MD, Ryan DH, Apovian CM, et al. "2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society." Circulation. 2014;129(25 Suppl 2):S102-S138. doi:10.1161/01.cir.0000437739.71477.ee
- Wing RR, Lang W, Wadden TA, et al. "Benefits of modest weight loss in improving cardiovascular risk factors in overweight and obese individuals with type 2 diabetes." Diabetes Care. 2011;34(7):1481-1486. doi:10.2337/dc10-2415
- Ryan DH, Yockey SR. "Weight loss and improvement in comorbidity: differences at 5%, 10%, 15%, and over." Curr Obes Rep. 2017;6(2):187-194. doi:10.1007/s13679-017-0262-y
- Wilding JPH, Batterham RL, Calanna S, et al. "Once-weekly semaglutide in adults with overweight or obesity." N Engl J Med. 2021;384(11):989-1002. doi:10.1056/NEJMoa2032183
- Jastreboff AM, Aronne LJ, Ahmad NN, et al. "Tirzepatide once weekly for the treatment of obesity." N Engl J Med. 2022;387(3):205-216. doi:10.1056/NEJMoa2206038
- Look M, Dunn JP, Kushner RF, et al. "Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study of adults with obesity or overweight." Diabetes Obes Metab. 2025;27(5):2720-2729. doi:10.1111/dom.16275
- Neeland IJ, Linge J, Birkenfeld AL. "Changes in lean body mass with glucagon-like peptide-1-based therapies and mitigation strategies." Diabetes Obes Metab. 2024;26 Suppl 4:16-27. doi:10.1111/dom.15728
- Helms ER, Aragon AA, Fitschen PJ. "Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation." J Int Soc Sports Nutr. 2014;11:20. doi:10.1186/1550-2783-11-20
- Garthe I, Raastad T, Refsnes PE, Koivisto A, Sundgot-Borgen J. "Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes." Int J Sport Nutr Exerc Metab. 2011;21(2):97-104. doi:10.1123/ijsnem.21.2.97
- Chaston TB, Dixon JB, O'Brien PE. "Changes in fat-free mass during significant weight loss: a systematic review." Int J Obes (Lond). 2007;31(5):743-750. doi:10.1038/sj.ijo.0803483
- Cava E, Yeat NC, Mittendorfer B. "Preserving healthy muscle during weight loss." Adv Nutr. 2017;8(3):511-519. doi:10.3945/an.116.014506
- Villareal DT, Aguirre L, Gurney AB, et al. "Aerobic or resistance exercise, or both, in dieting obese older adults." N Engl J Med. 2017;376(20):1943-1955. doi:10.1056/NEJMoa1616338
- Gaddey HL, Holder KK. "Unintentional weight loss in older adults." Am Fam Physician. 2021;104(1):34-40. PMID:34264616
How this calculator differs from typical weight loss percentage calculators
Most weight loss percentage calculators online stop at the division. They return a percent, maybe a pounds figure, and leave you to guess whether the number is good. That misses the only reason anyone looks the percent up, which is to know what it means for their health and whether they are on track.
This tool puts the percent next to the thresholds the research actually uses: the 3 to 5% band where the obesity guideline says benefits begin, the 5 to 10% initial goal, and the 10 and 15% tiers from Look AHEAD and the Ryan and Yockey review. It shows the exact weight at your next milestone instead of making you work it out. It judges weekly pace as a percent of body weight, so a 300 lb and a 150 lb person get a fair comparison, and it treats slower-than-textbook progress as normal rather than as a failure. For GLP-1 users it states the STEP 1 and SURMOUNT-1 results with their populations, doses and durations, and it refuses to turn them into dosing advice. It also validates every input, flags a current weight or goal that cannot be right, and warns when a pace is fast enough to deserve a clinician's attention.
Frequently Asked Questions
How do you calculate weight loss percentage?
Subtract your current weight from your starting weight, divide the result by your starting weight, and multiply by 100. Someone who started at 220 lb and now weighs 204 lb has lost 16 lb, and 16 divided by 220 is 0.073, so the weight loss percentage is 7.3%. Use the same unit for both weights, and use a weekly average rather than a single weigh-in if your weight moves around from day to day.
What percentage of weight loss is clinically significant?
About 5%. The 2013 AHA/ACC/TOS guideline for managing overweight and obesity (Jensen et al. 2014, Circulation) says a modest, sustained loss of 3 to 5% of body weight produces clinically meaningful health benefits, and that greater losses produce greater benefits. It recommends losing 5 to 10% of baseline weight within six months as the initial goal. At a 5% loss the guideline reports average blood pressure reductions of about 3 mm Hg systolic and 2 mm Hg diastolic.
How much weight is 5 percent of my body weight?
Multiply your weight by 0.05. For someone who weighs 200 lb, 5% is 10 lb, so the 5% milestone is 190 lb. At 250 lb it is 12.5 lb, and at 300 lb it is 15 lb. In metric, 5% of 100 kg is 5 kg and 5% of 80 kg is 4 kg. For 10%, multiply by 0.10, and for 15%, multiply by 0.15.
What is a healthy rate of weight loss per week as a percentage?
Most people do well at 1% of body weight a week or less. Helms and colleagues (2014, Journal of the International Society of Sports Nutrition) recommend 0.5 to 1% a week to keep as much muscle as possible. In Garthe et al. 2011, athletes who lost about 0.7% a week while lifting gained lean mass, while a faster group did not. For a 200 lb person, 0.5 to 1% is 1 to 2 lb a week. Slower than that is common and still counts if it holds.
How much weight do people lose on semaglutide or tirzepatide?
In the STEP 1 trial (Wilding et al. 2021, New England Journal of Medicine), 1,961 adults with obesity or overweight took semaglutide 2.4 mg once a week with a lifestyle program for 68 weeks and lost an average of 14.9% of body weight, compared with 2.4% on placebo. In SURMOUNT-1 (Jastreboff et al. 2022, New England Journal of Medicine), 2,539 adults took tirzepatide at 5, 10 or 15 mg a week for 72 weeks and lost an average of 15.0%, 19.5% and 20.9%, compared with 3.1% on placebo. These are trial averages, not dosing advice. Doses are set by the prescriber.
How much of the weight I lose is muscle?
It depends mostly on how hard you diet and whether you lift. A 2007 systematic review by Chaston and colleagues found that deeper calorie restriction raised the share of weight lost as fat-free mass, and that exercise lowered it. In the SURMOUNT-1 body composition substudy (Look et al. 2025), about 25% of the weight lost on tirzepatide was lean mass, the same share as on placebo. In Villareal et al. 2017, dieting older adults who did resistance training lost 2 to 3% of their lean mass, compared with 5% for those who did aerobic training only.
When should weight loss be a concern?
When you are not trying to lose it, or you cannot explain it. Clinicians usually define unintentional weight loss as losing 5% or more of body weight over 6 to 12 months; Gaddey and Holder 2021 (American Family Physician) use that definition for adults over 65. It warrants a visit to a clinician at any age. Very fast loss that you did intend, weight loss during pregnancy, and weight loss alongside an eating disorder or a history of one also need medical input rather than a calculator.