Weight Loss Percentage Calculator
Enter your starting and current weight to calculate your percentage change, track your progress and see how close you are to your target.
Target progress
This tool tracks changes in scale weight only. It does not measure body fat, muscle mass or overall health. Results are estimates based on the values entered.
How to Calculate Weight Loss Percentage
Tracking changes in your weight can help you understand how your measurements have changed over time. A percentage gives you a way to compare that change with your starting weight, rather than looking only at the number of kilograms or pounds lost.
This calculator lets you enter your starting weight and current weight to see the percentage of weight lost or gained. You can also set a target weight, enter dates and track your progress over time.
How to Calculate Weight Loss Percentage
To calculate the percentage of weight lost, subtract your current weight from your starting weight, divide the result by your starting weight, and multiply by 100.
Formula:
Weight loss percentage = ((Starting weight − Current weight) ÷ Starting weight) × 100
For example, suppose your starting weight was 90 kg and your current weight is 84 kg.
- Starting weight: 90 kg
- Current weight: 84 kg
- Weight lost: 6 kg
- Percentage lost: (6 ÷ 90) × 100
- Result: 6.67%
This means your current weight is 6.67% lower than your starting weight.
If your current weight is higher than your starting weight, the calculator identifies the change as weight gained.
How to Use This Calculator
- Choose a unit: Select kilograms, pounds or stone.
- Enter your starting weight: Add the weight you are using as your baseline.
- Enter your current weight: Enter your latest measurement.
- Set a target (optional): Add a target weight to calculate progress toward it.
- Add dates (optional): Enter both dates to calculate elapsed time and average weekly change.
- Review your results: The calculator updates automatically as you change your inputs.
- Copy your results: Use the copy button to save or share your calculation.
Understanding Your Results
Your percentage change shows how much your weight has changed relative to your starting measurement. The weight-change result displays the difference in your selected unit.
If you enter a target, the calculator also estimates your progress toward it. Progress can be below 0% if your weight has moved in the opposite direction, or above 100% if you have passed the target.
When both dates are provided, the calculator displays the elapsed time and average weekly weight change. This is a simple mathematical average, not a prediction of future results.
Frequently Asked Questions
How do I calculate the percentage of weight I have lost?
Subtract your current weight from your starting weight, divide that difference by your starting weight and multiply by 100. For example, going from 80 kg to 76 kg is a 5% reduction from the starting weight.
Can I calculate weight gain with this tool?
Yes. Enter a current weight that is higher than your starting weight. The calculator will identify the change as weight gained and show the percentage relative to your starting measurement.
Can I use pounds or stone instead of kilograms?
Yes. You can choose kilograms, pounds or stone from the unit selector. The calculator converts your entered values when you switch units.
How is progress toward a target weight calculated?
The calculator compares the difference between your starting weight and current weight with the difference between your starting weight and target weight. This provides the percentage of the planned change completed.
Does the calculator show how long weight change took?
Yes. Enter both a starting date and a current date. The tool calculates the number of elapsed days and, when the dates differ, the average weekly weight change.
Is weight loss percentage the same as body fat percentage?
No. Weight loss percentage measures the change in total body weight relative to a starting measurement. Body fat percentage estimates the proportion of body weight made up of fat. They are different measurements.
Can this calculator predict future weight loss?
No. It calculates changes from the values you enter and does not predict future weight. Actual weight can fluctuate and may be affected by many factors.
Disclaimer: This calculator is intended for general informational purposes. It does not assess health, body composition or whether a particular weight is appropriate for an individual. Consult a qualified healthcare professional for personalized guidance.