How do you calculate weight loss percentage?
To calculate weight loss percentage, subtract your current weight from your starting weight, divide by your starting weight, then multiply by 100. Going from 200 lb (90.7 kg) to 186 lb (84.4 kg) is a 14 lb loss, or 7%. The CDC notes that losing 5% could lower the risk of some chronic diseases.
Say you're down 12 pounds, and a friend is down 12 pounds too. But she started 60 pounds lighter than you. Did you both make the same progress? Not quite, and that's why your weight loss percentage tells a clearer story than pounds alone.
What does weight loss percentage mean?
It is the share of your starting weight that you've lost. It turns "I lost 12 pounds" into "I lost 6% of my body weight" (if you started at 200 lb, or 91 kg).
Why bother? Because percentage scales to your size. Look at the same 10 lb (4.5 kg) loss from three different starting points:
| Starting weight | Lost | Weight loss percentage |
|---|---|---|
| 150 lb (68 kg) | 10 lb (4.5 kg) | 6.7% |
| 200 lb (91 kg) | 10 lb (4.5 kg) | 5.0% |
| 250 lb (113 kg) | 10 lb (4.5 kg) | 4.0% |
Same pounds, very different progress.
Health agencies like the CDC and NIH also talk about weight loss in percentages. So this number helps you compare your progress to their guidance.
What is the weight loss percentage formula?
Weight loss % = (starting weight minus current weight) ÷ starting weight × 100. You only need two numbers: your starting weight and your current weight.
- Subtract your current weight from your starting weight. That's how much you've lost.
- Divide that number by your starting weight.
- Multiply by 100. That's your percentage.
Example in pounds
You started at 200 lb and now weigh 186 lb.
- 200 minus 186 = 14 lb lost
- 14 ÷ 200 = 0.07
- 0.07 × 100 = 7%
Example in kilograms
You started at 80 kg (176 lb) and now weigh 76 kg (168 lb).
- 80 minus 76 = 4 kg lost
- 4 ÷ 80 = 0.05
- 0.05 × 100 = 5%
The formula works in any unit. Just make sure both weights use the same one. Don't mix pounds and kilograms in the same sum.
If the answer comes out negative, your weight went up, not down. And if you'd rather skip the math, our weight loss percentage calculator does it in a second.
How do you find a goal weight for a set percentage?
Multiply your starting weight by 1 minus your goal percentage as a decimal. For a 5% goal, multiply by 0.95. For 10%, multiply by 0.90.
Goal weight = starting weight × (1 minus your percentage as a decimal)
| Starting weight | 5% goal | 10% goal |
|---|---|---|
| 150 lb (68 kg) | 142.5 lb (64.6 kg) | 135 lb (61.2 kg) |
| 200 lb (91 kg) | 190 lb (86.2 kg) | 180 lb (81.6 kg) |
| 250 lb (113 kg) | 237.5 lb (107.7 kg) | 225 lb (102.1 kg) |
| 300 lb (136 kg) | 285 lb (129.3 kg) | 270 lb (122.5 kg) |
A smaller, clear goal like this can make a big goal feel a lot more doable.
Why is 5% weight loss a big deal?
Because health agencies link it to real benefits. You don't have to lose a huge amount to see them.
- The CDC says a 5% weight loss, which is 10 pounds for someone who weighs 200 pounds, could lower the risk for some chronic diseases, such as heart disease, prediabetes, and type 2 diabetes.
- The National Heart, Lung, and Blood Institute (NHLBI) says health professionals recommend losing 5% to 10% of your starting weight over about 6 months. It adds that even 3% to 5% can lower blood triglycerides and blood sugar, and the risk of type 2 diabetes. Losing more than 3% to 5% can improve blood pressure and cholesterol.
- The NIDDK says that people at risk for type 2 diabetes may be able to prevent or delay it by losing at least 5% to 7% of their starting weight. For a 200 lb (91 kg) person, that is about 10 to 14 lb (4.5 to 6.4 kg).
A note for women
The NIDDK also notes that women with obesity who lose 5% of their body weight may increase their chances of having regular periods, ovulating, and becoming pregnant. If this applies to you, your doctor is the best person to talk through a plan with.
How fast should your weight loss percentage go up?
For most people, about 0.5% to 1.3% of body weight a week, depending on size. The CDC says people who lose weight gradually, about 1 to 2 pounds (0.5 to 0.9 kg) a week, are more likely to keep it off.
In percentage terms, for a 200 lb (91 kg) person, that's about 0.5% to 1% of body weight a week. For a 150 lb (68 kg) person, it's about 0.7% to 1.3% a week.
Why does progress slow down?
Weight loss usually slows over time, even if you keep eating the same way. Many people find this frustrating, so here is why it happens.
A 2011 modeling study in The Lancet, led by Kevin Hall at the NIH, found that body weight responds slowly to a change in calories. It takes about a year to get halfway to your new stable weight.
That's also why the old rule that "3,500 calories equals 1 pound" overestimates long-term weight loss.
So a slower month later on is normal. It doesn't mean you did something wrong. The NIH's free Body Weight Planner is built on Hall's model if you'd like a more realistic forecast.
Does the math change on a GLP-1 medicine?
No. The math is exactly the same if you're taking a GLP-1 medicine like Ozempic, Wegovy, Mounjaro, or Zepbound.
Your care team may track this number too. It's a handy way to talk about progress with them.
But the scale can't tell you what kind of weight you lost. The 2025 joint advisory on nutrition with GLP-1 medicines lists muscle and bone loss as key concerns. It recommends resistance training and enough protein: 1.2 to 1.6 g of protein per kg of body weight a day during active weight loss.
So alongside your weight loss percentage, keep an eye on your protein and your strength. Our guide on protein on Ozempic covers easy protein-first meals. To track body composition too, our body fat calculator is a good companion.
How do you track weight loss percentage accurately?
Weigh yourself the same way each time, and look at the trend rather than single days. A few simple habits make your numbers more reliable.
- Weigh the same way each time. Same scale, same time of day, similar clothes.
- Record your true starting weight. Your percentage is only as good as that first number.
- Look at the trend. Check your percentage every 2 to 4 weeks, not every morning.
- Pair it with a plan. Our calorie deficit calculator can help you set a daily calorie target that fits a steady pace.
When to talk to a professional
If you are pregnant or breastfeeding, have a history of an eating disorder, have diabetes or kidney disease, or take medicines, talk to your doctor or a registered dietitian before setting a weight loss goal. They can help you choose a safe target.
My take
What I find interesting is how much a percentage changes the mood of a weigh-in. Ten pounds can feel small on a big frame. But 5% is a milestone the CDC and NIH both point to, and that is worth noticing.
The bottom line on weight loss percentage
Subtract your current weight from your starting weight, divide by your starting weight, and multiply by 100. That's it.
This one number puts your progress in context. It lets you compare fairly, set clear goals, and see when you've hit meaningful milestones like 5%. According to the CDC and NIH, that first 5% can matter for your health.
Give it a try with your own numbers in our weight loss percentage calculator. Every percent is progress, and you've got this.