How to Calculate a Credit Card Surcharge on a Selling Price

In some cases, it is acceptable for merchants to charge you a surcharge on a small credit card purchase. The reason is that the credit card fees might eat up the merchant’s profit. If a customer pays $1 for a product that the merchant makes a 30 cent profit on and the credit card processing fee is 30 cents per transaction plus 3 percent of the price, the merchant actually loses money. Estimating the surcharge the merchant charged on the transaction requires a bit of math.

Determine the total final price charged on your credit card. Say, for instance, the amount is $5.00.

Determine the selling price for the product you purchased and deduct it from the total amount charged. For instance, if the selling price is $3.00, the remaining amount is $2.00.

Deduct the sales tax fee for the product (if it is a taxable item) based on the tax rate for the state where you purchased the item. If the sales tax rate is 7 percent, the sales tax fee in this example is $0.21 ($3 times .07). The total amount of the credit card surcharge is $2.00 less $0.21 or $1.79.

Divide the credit card surcharge by the selling price if you want to determine the surcharge as a percentage of the selling price. In this case, it is $1.79 divided by $3 or 60 percent.