Credit Card Processing Cost-Calculators Are Hypothetical at Best and Comical at Worst.

Interchange is responsible for most credit card processing expenses, and it’s impossible to predict interchange fees until a transaction actually happens. Estimating costs using a business’s processing profile to predict interchange is possible, but such estimates will never produce a spot-on figure.

Never choose a processor based on the estimated total cost of processing. Instead, concentrate only on the processor’s markup portion of the cost. The estimated markup will be far more accurate and useful than the total estimated expense.