About the Weight Change Percentage Calculator
Percentage of body weight lost or gained between two weigh-ins, and the change per week.
Also known as: percent weight loss, body weight percentage change, weight loss percentage.
How to use this calculator
- Enter starting weight, current weight, weeks between.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
% change = (now − start) ÷ start × 100
Worked example
Using the values pre-filled in the calculator above:
- Starting weight = 92
- Current weight = 85.5
- Weeks between = 10
the calculator returns:
- Change: -7.07%
- Absolute change: 6.5
- Per week: 0.65
- Direction: Loss