This health calculator expresses weight change as absolute loss and percentage relative to a starting weight.
Health
Weight Loss Percentage Calculator
Calculate absolute and percentage weight loss from starting and current weight.
Calculator
About this calculator
Formula notes
weight loss = starting weight - current weight; weight loss percentage = weight loss / starting weight x 100.
Worked examples
- Example: 100 kg starting and 90 kg current is 10 kg lost and a 10% weight loss.
- Going from 80 kg to 68 kg is a 12 kg loss and a 15% weight loss relative to the starting weight.
How to use it
- Enter starting weight and current weight in the same unit.
- Confirm the current weight is below starting.
- Read absolute loss and percentage.
Frequently asked questions
Does water weight or lean mass change the result?
The percentage is a simple mass ratio; it does not distinguish fat, muscle, water, or other tissue.
Is this medical advice?
No. Use a healthcare provider for safe targets; rapid or severe loss can warrant evaluation.
Limits and interpretation
- Weight changes from day to day; one reading can include water, food, glycogen, and clothing differences rather than a stable trend.
- Extremely low starting or current weights and rapid loss should be discussed with a healthcare provider.