Weight Loss Percentage Calculator

Weight loss percentage tells you what share of your starting body weight you have lost. Subtract your current weight from your starting weight, divide the result by your starting weight, and multiply by 100. Because the units cancel out, the formula gives the same answer in pounds or kilograms.

A Worked Example

Say you started at 200 lbs and weigh 182 lbs today. You have lost 18 lbs, and 18 ÷ 200 × 100 = 9.0% of your starting weight. If your goal is 170 lbs, you set out to lose 30 lbs, which is 15% of your starting weight, and 18 ÷ 30 × 100 means you are 60% of the way there, with 12 lbs to go. If those 18 lbs came off over 12 weeks, your average is 9.0 ÷ 12 = 0.75% of body weight per week, or 1.5 lbs a week.

Why Percent Beats Pounds

Raw pounds ignore how big you were at the start. Ten pounds is 6.7% of body weight for someone who began at 150 lbs, but only 3.3% for someone who began at 300 lbs. Health guidelines and the trials behind them set their targets as percentages, so a percentage is the number you can compare against them. It also lets two people of different sizes, or the same person in pounds and kilograms, compare progress fairly.

The CDC notes that even modest weight loss can improve blood pressure, cholesterol and blood sugar, and uses the example of a 5% loss, which is 10 lbs for a 200-lb person. The National Heart, Lung, and Blood Institute says health professionals recommend losing 5% to 10% of initial weight over about 6 months, and that losing more than 3% to 5% can improve blood pressure and cholesterol.

5%: The First Marker

In a randomized trial in adults with obesity, losing about 5% of body weight improved insulin sensitivity in the liver, muscle and fat tissue and improved beta-cell function. In the Diabetes Prevention Program, a lifestyle program aimed at a loss of at least 7% cut the incidence of type 2 diabetes by 58% compared with placebo in people with elevated blood sugar.

10%: Bigger Risk-Factor Gains

In Look AHEAD, a study of 5,145 adults with type 2 diabetes, people who lost 5% to under 10% in a year had 3.5 times the odds of a 0.5-point drop in HbA1c compared with people whose weight stayed stable, along with better odds of lower blood pressure, lower triglycerides and higher HDL cholesterol. Those who lost 10% to 15% had even greater odds of improvement in most risk factors.

15%: Where Some Conditions Respond

A review in Current Obesity Reports found that for some conditions, including obstructive sleep apnea and non-alcoholic steatohepatitis (a form of fatty liver disease), a loss of 10% to 15% is needed for clinical improvement. The same review stresses that the target should be health improvement rather than a number on the scale, so these marks are reference points to discuss with your clinician, not pass-or-fail grades.

Typical Weekly Rates

The CDC says people who lose weight at a gradual, steady pace of about 1 to 2 lbs a week are more likely to keep it off than people who lose it faster. As a percentage, that range depends on your size: 0.5% to 1% a week at 200 lbs, and about 0.7% to 1.3% a week at 150 lbs. NHLBI's 5% to 10% over 6 months averages roughly 0.2% to 0.4% a week. Enter your weeks elapsed above to see your own average beside the CDC range. A calorie deficit drives the trend, and the weight loss calculator projects a goal date from yours.

Your percentage counts everything the scale counts, not only fat. Three things are worth keeping in mind when you read it.

• Early losses include water. The body stores carbohydrate as glycogen bound to three to four parts water, according to research on very-low-calorie diets. Using up glycogen in the first days of a diet releases that water, which is why the first week often looks faster than the weeks after it.
• Some of the loss is lean mass. A widely cited rule holds that about a quarter of weight lost by dieting is fat-free mass and three quarters is fat; a critical review of that rule notes the share varies with age, activity and exercise. Read more in muscle vs fat weight.
• Track the trend, not single days. Because water moves the scale from day to day, compare weekly averages. If your percentage stops moving for several weeks, see why weight loss plateaus, and recheck your energy needs with the TDEE calculator.