Payment Gateway Fee Comparison Calculator

Written out

A meaningful comparison uses total cost over a representative period rather than headline rates: (volume × rate) + (transactions × fixed) + monthly fees + any gateway, PCI or minimum charges.

The comparison has to run on your actual transaction distribution, because the fixed component and the monthly charges affect low-volume and small-transaction businesses far more than the percentage does.

In practice

1,000 transactions averaging $58, $58,000 a month. Processor A at 2.9% + $0.30 with no monthly fee: $1,982. Processor B at 2.5% + $0.25 with a $79 monthly fee: $1,779. Processor C at interchange plus 0.4% + $0.10 with a $49 monthly: about $1,400.

C wins by $582 a month against A. But at 200 transactions averaging $58, $11,600: the picture reverses: A costs $396, B costs $404, and C costs about $327 including the monthly.

The ranking depends on volume, and any comparison run at one volume level does not transfer to another. Re-running it as the business grows is the point.

The limitations

Rate is the most visible variable and rarely the most important one. Settlement speed, chargeback handling, supported payment methods, checkout conversion and integration effort all have larger effects on a business than half a point of rate.

Conversion in particular dwarfs everything else. A processor whose checkout converts one percentage point better is worth far more than a rate difference of the same size, because conversion applies to revenue and rate applies to cost.

Putting it to use

Build the comparison on twelve months of your own transaction data, including the distribution rather than the average. Then re-run it annually, because your volume moves and their pricing changes.

Then weigh conversion alongside cost. Testing two checkouts on split traffic is more work than comparing rate cards and it answers the question that actually matters.

The switching costs nobody prices

Migrating processor means re-integrating, re-testing, migrating stored payment credentials for subscriptions, updating reconciliation, and carrying a period where two systems are live. For a business with recurring billing it is a substantial project.

Stored card migration is the specific item that catches people. Moving tokenised cards between processors is possible through a PCI-compliant migration but it is not automatic, and getting it wrong means asking every subscriber to re-enter their card, with the churn that follows.

That cost has to clear before a rate saving is worth acting on. A $500 a month saving on a migration costing $8,000 in time and risk pays back in sixteen months, which is a reasonable case; the same saving on a subscription business facing re-entry churn frequently is not.

There is also this: settlement timing, which is a financing cost rather than a fee. A processor settling in two days against one settling in seven is providing five days of working capital on every transaction.

On $58,000 of monthly volume that difference is roughly $9,500 of permanently released cash, which for a growing business is worth more than a modest rate advantage and never appears in a rate comparison.