Calculadora de Porcentagem de Perda de Peso
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
% = (inicial − atual) / inicial × 100
About this calculator
The Weight Loss Percentage Calculator is a practical tool to measure progress in diets or weight loss programs. It calculates the percentage of weight lost based on initial and current weight, using the formula: % loss = (initial weight - current weight) / initial weight × 100. This percentage is more informative than the simple difference in kilograms, as it accounts for starting weight, allowing fairer comparisons among people with different body types.
How to use the calculator: enter your initial weight (before loss) and your current weight. The result shows the percentage of weight you have already lost. For example, if you weighed 80 kg and now weigh 72 kg, the loss was 10%. This metric is widely used by health professionals to evaluate the effectiveness of nutritional interventions and track patient progress over time.
When to use: ideal for those undergoing weight loss, whether on their own or with medical supervision. Also useful in weight loss competitions (such as wellness challenges) or to compare results across different periods. It can be applied both for fat loss and for weight reduction due to water retention, but context should be considered.
Cautions: the calculator does not replace a full professional evaluation. Healthy weight loss is gradual (0.5 to 1 kg per week). Very high percentages in a short period may indicate excessive caloric restriction or health issues. Additionally, the percentage does not distinguish between fat loss and lean mass loss. For a more accurate analysis, consult a nutritionist or doctor.
Frequently asked questions
What is the difference between losing weight in kilograms and in percentage?
Losing 5 kg can be a lot for a 60 kg person (8.3%) and little for a 100 kg person (5%). The percentage relativizes the loss, showing the proportional effort relative to initial weight.
Can I use this calculator for weight gain?
No, it is designed only for loss. For gain, use a weight gain percentage calculator, which uses a similar formula but with a reversed sign.
What is a healthy percentage of weight loss per month?
Generally, 5% to 10% of initial weight per month is considered safe, but this varies. Losses above 2% per week can be harmful.
Does the calculator work for spot fat loss?
No, it measures total weight loss, not spot reduction. Measuring circumferences (waist, hips) is more suitable for assessing localized fat.
Do I need to use kilograms or pounds?
The calculator accepts any unit, as long as both are in the same unit. The result is dimensionless (percentage).