In everyday finance fees, losses, and refunds are usually calculated using a difference-based formula: subtracting the new value from the original value and dividing by the original price. While this method is correct and used worldwide. It's not the only formula to arrive at a correct result. Here I propose a new technique that can maybe offer a new perspective. 

To explain more, this article presents an alternative, ratio-based technique that you can use to reach the same results but with a different way of calculation. 

The Common Method (Difference-Based)

The known formula for calculating a loss percentage is

Fee % = (old price - new price) / old price x 100

This approach focuses on what was lost. And is used everywhere. 

The Alternative Technique (Ratio-Based)

The technique I proposed here starts from a different idea:

Instead of asking, “How much was lost?” We ask, “How much value remains?” How much remains is the main question in this technique. It gives a different perspective on the same idea. 

Step 1: Calculate retained value.

Retained value % = new price / old price x 100 

Step 2: Derive the fee.

Fees % = 100 - Retained value %

As simple as that. So complex formulas are as simple as the one used. But different. 

You can try it yourself or see the example below. 

Example

Original price: 10

Returned price: 9.25

Retained value % = 9.25/10 × 100 = 92.5%

Fee % = 100 - 92.5 = 7.5% 

The result is exactly the same as the standard method. But different formula. 

Are These the Same Formula?

• No—they are not the same in form. Each one is unique in its own way. 
• Yes—they are mathematically equivalent. Giving the same results. 

An Intuitive Analogy

It’s like cutting an apple:

• One person slices it from top to bottom. 
• Another cuts it in half first. 

Different cuts, same apple. You get the idea. Every person has his own way of calculating. Different ways the same results. You can choose. 

Conclusion

This technique does not introduce a new financial rule, nor is it a new groundbreaking discovery. Instead, it offers a different lens, one that focuses on retained value rather than deducted value. 

Every formula has its own benefits. Maybe someone will benefit from this formula other than the other. Or maybe you find the known one more helpful. 

Hope you find it helpful.