How to calculate the percentage of weight lost?

Here's an example: We are looking for the percentage weight loss. Formula: (Weight lost / Original weight) × 100. Percentage loss = (Lost weight / Original weight) × 100.

Weight Loss Percentage - Calculate Weight Decrease Percentage

I was kg and I lost kg...
What percentage of body weight did I lose?

Contextual hints will appear here as you calculate

Incomplete data. Enter all required values to see the calculations.

Answer: You lost % of your body weight.

Round calculations to 2 decimal places

Type of calculation: Calculating percentage decrease.
How to use the calculator: First, find your new weight (80 kg - 8 kg = 72 kg). Then use the Percentage Change CALCULATOR ("What is the percentage change from the Original value to the New value?"). Enter the starting weight 80 [Original] and the new weight 72 [New]. It will calculate the drop.
The formula:
First, let's get the new weight:
New weight = Old weight - Weight lost
New weight = 80 kg - 8 kg = 72 kg
Now, find the percentage change from 80 kg to 72 kg.
Formula: ((New weight - Old weight) / Old weight) × 100%
Percentage change = ((72 - 80) / 80) × 100% = (-8 / 80) × 100% = -0.1 × 100% = -10% (minus means weight loss)
Another way (using "Part-to-Whole Percentage CALCULATOR"): You can simply check what percentage 8 kg (lost) is out of 80 kg (starting weight). Use the Part-to-Whole Percentage CALCULATOR ("What percentage of Y is Z?"). Enter 80 [Y] and 8 [Z]. You get 10%. Since it's a loss, that's a 10% decrease.