Weight Loss Percentage Calculator

How this calculator works

The calculator subtracts your current weight from your starting weight. It divides the result by your starting weight and multiplies by 100. The unit cancels out in the division, so kilograms, pounds, and stone give the same percentage.

The goal progress shows the part of your planned loss that you already lost. The weekly pace divides the weight you lost by the number of weeks. The calculator compares your pace with the gradual, steady pace of about 1 to 2 pounds (about 0.45 to 0.9 kg) per week. The CDC states that people who lose weight at this pace are more likely to keep the weight off than people who lose weight faster ^[1].

A percentage is a useful measure because health guidance uses percentages. The CDC states that even a modest loss, such as 5% of body weight, can help improve blood pressure, cholesterol, and blood sugar ^[1]. The NHLBI states that health professionals recommend a loss of 5% to 10% of initial weight over about 6 months ^[2].

Limits: the result does not show if the weight you lost is fat, muscle, or water. Daily weight changes with water, food, and time of day, so compare weights taken at the same time of day.

How to calculate your weight loss percentage: worked examples

Example 1 (pounds): you started at 200 lb and now weigh 180 lb. You lost 200 - 180 = 20 lb. 20 / 200 x 100 = 10%.

Example 2 (kilograms): you started at 90 kg and now weigh 85.5 kg. You lost 4.5 kg. 4.5 / 90 x 100 = 5%.

Example 3 (stone): you started at 15 st (210 lb) and now weigh 14 st 3.5 lb (199.5 lb). You lost 10.5 lb. 10.5 / 210 x 100 = 5%.

Example 4 (goal and pace): you started at 100 kg, your goal is 85 kg, and you now weigh 94 kg after 10 weeks. You lost 6 kg, which is 6%. Your planned loss is 15 kg, so you are 6 / 15 x 100 = 40% of the way to your goal, with 9 kg to go. Your average pace is 6 / 10 = 0.6 kg per week.

What the 5% and 10% milestones mean

The 5% milestone is a common first goal. The NIDDK gives the example that losing 5% of your body weight over 6 months may be a good initial goal ^[3]. For a person who weighs 200 lb, 5% is 10 lb.

Smaller losses can also matter. The NHLBI states that a loss of 3% to 5% of current weight can lower triglycerides and blood glucose ^[2]. The NIDDK states that people at risk for type 2 diabetes may prevent or delay it by losing at least 5% to 7% of their starting weight ^[4].

The 10% milestone is the upper end of the 5% to 10% range over about 6 months that the NHLBI describes ^[2]. Work with a health care professional to set a goal and a time frame that fit your health.

Weight loss percentage on GLP-1 medicines

Clinical trials of GLP-1 based medicines report results as a percentage of body weight, so this calculator lets you use the same measure. The numbers below are trial averages. They are not a prediction for one person.

• In the STEP 1 trial, adults without diabetes who took semaglutide 2.4 mg once a week, plus a lifestyle intervention, had a mean body weight change of -14.9% after 68 weeks, compared with -2.4% with placebo ^[5].
• In the SURMOUNT-1 trial, the mean weight change after 72 weeks was -15.0% with 5 mg of tirzepatide, -19.5% with 10 mg, and -20.9% with 15 mg, compared with -3.1% with placebo ^[6].

Results differ between people, doses, and treatment lengths. If you take a prescribed medicine, ask your prescriber which pace and which goal are right for you. Protein intake is a common topic during GLP-1 treatment; see the GLP-1 protein calculator.

How to track your progress

• Weigh yourself at the same time of day, for example in the morning before you eat.
• Look at the trend over several weeks, not at one day.
• Use the same starting weight each time you calculate, so the percentages stay comparable.
• Track what you eat. The calorie calculator gives an estimate of your daily calorie needs, and counting calories helps you stay within that target.