How to Calculate Weight Loss Percentage
Weight Loss % = ((Starting Weight − Current Weight) / Starting Weight) × 100. For example, from 85kg to 76kg: ((85-76)/85) × 100 = 10.6% lost.
Using This Calculator
Use Mode 3 (% Change). Enter your starting weight as "Original Value" and your current weight as "New Value." A negative result shows your weight loss percentage.
Health Impact of Weight Loss Percentages
- 3–5% body weight loss: Improves blood sugar, triglycerides, and diabetes risk
- 5–10% loss: Lowers blood pressure, improves cholesterol, reduces joint strain
- 10–15% loss: Significant cardiovascular benefit, improved sleep apnea
- 20%+ loss: Major health transformation, often considered medically significant
Healthy Weight Loss Rate
The NHS and WHO recommend losing 0.5–1kg per week as a safe, sustainable rate. This equals roughly 2–4kg per month. Faster loss risks muscle loss and nutritional deficiencies. Calculate your expected loss timeline using these benchmarks.
Frequently Asked Questions
How do I calculate my weight loss percentage?
Weight Loss % = ((Start Weight − Current Weight) / Start Weight) × 100. If you started at 90kg and now weigh 81kg: (9/90) × 100 = 10%.
Is a 10% weight loss significant?
Yes, medically significant. Losing 10% of body weight has proven benefits for blood pressure, blood sugar, cholesterol, and joint health.
How long does it take to lose 10% of body weight?
At the recommended rate of 0.5–1kg/week, losing 10% of a 90kg body (9kg) would take 9–18 weeks.
Does muscle weigh more than fat?
Muscle is denser than fat — muscle tissue takes up less space. That's why body composition (fat % vs. muscle %) matters more than just scale weight.