Free Tool
Weight Change Calculator
Compare two weight measurements and see the difference as a number and percentage. No targets or timeline predictions.
Enter two measurements to compare them.
How the comparison works
The calculator subtracts the starting measurement from the current measurement. It then divides that change by the starting measurement to express it as a percentage. Pounds and kilograms produce the same percentage when both entries use the same unit.
A single comparison cannot show a trend or explain why weight changed. Day-to-day measurements can move with hydration, meals, clothing, and measurement conditions.
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Frequently asked questions
How is percentage weight change calculated?
Subtract the starting weight from the current weight, divide the difference by the starting weight, and multiply by 100. A negative result is a decrease and a positive result is an increase.
Can I use pounds or kilograms?
Yes. Use the same unit for both measurements. The numeric difference will use that unit, while the percentage is the same either way.
Does this calculator set a healthy target weight?
No. It only compares two measurements. A healthy range depends on broader health context and should be discussed with a qualified clinician.
Does this result show a weight trend?
No. Two measurements show a single change, not a trend. Repeated measurements taken under similar conditions provide more context.
Does this calculator predict future weight change?
No. It does not project a goal date or assume a steady rate of change.