Free tool · Body
Weight loss percentage calculator
Short answer
Weight loss percentage = (starting weight − current weight) ÷ starting weight × 100. Going from 200 lb to 188 lb is 6.0% lost; over 8 weeks that is 1.5 lb a week. The NHLBI's adult guideline sets an initial goal of about 10% of starting weight over about 6 months, at 1–2 lb a week.
Last reviewed 28 October 20261 published sourcesNot medical advice
Reps keeps track of this for you on iPhone, iPad and Apple Watch.
Get Reps freeWeight loss percentage calculator
Use the same scale at the same time of day for both weights. Weeks are optional and add a weekly rate.
Enter your starting and current weight.
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| Starting weight | 10% to lose | Goal weight |
|---|---|---|
| 150 lb (68 kg) | 15 lb | 135 lb |
| 180 lb (82 kg) | 18 lb | 162 lb |
| 210 lb (95 kg) | 21 lb | 189 lb |
| 240 lb (109 kg) | 24 lb | 216 lb |
| 270 lb (122 kg) | 27 lb | 243 lb |
What the guideline says
The National Heart, Lung, and Blood Institute's 1998 clinical guideline for adults with overweight or obesity recommends that "the initial goal of weight loss therapy should be to reduce body weight by approximately 10 percent from baseline", with further loss attempted afterwards if indicated (NHLBI, 1998).
It describes a rate of about 1 to 2 lb a week for 6 months, and calls 6 months a reasonable time line for a 10% reduction (NHLBI, 1998).
Planning the next stretch
See how long a goal might take with the calorie deficit calculator, and estimate your maintenance calories with the TDEE calculator.
Keep the trend honest
Reps reads your weight from Apple Health and logs meals by photo, voice or text, so you can see the trend and what is behind it.
Free to download · iPhone, iPad and Apple Watch
Common questions
How do I calculate weight loss percentage?
Subtract your current weight from your starting weight, divide by your starting weight and multiply by 100. Losing 12 lb from 200 lb is 6%.
What is a realistic first goal?
The NHLBI's clinical guideline recommends an initial goal of about 10% of starting weight, with about 6 months as a reasonable time line, then further loss if needed.
How fast should I lose weight?
The same guideline describes about 1 to 2 lb (0.45–0.91 kg) a week over 6 months. Early weeks often include water, so judge the trend over several weeks.
Sources
Figures on this page were checked against these publications on 28 October 2026.
- National Heart, Lung, and Blood Institute. Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report. NIH Publication No. 98-4083. National Institutes of Health; September 1998. www.nhlbi.nih.gov/files/docs/guidelines/ob_gdlns.pdf
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