Payment Gateway Comparison Calculator

This calculator puts two payment gateways head-to-head on total monthly cost, splitting your transaction volume into domestic and international shares so each gateway's international surcharge only applies where it actually would. For each gateway, domestic processing cost is volume times its percentage rate plus transaction count times its fixed per-transaction fee; international processing adds the gateway's international surcharge on top of its base rate for that slice of volume. A flat monthly subscription fee (if any) is added to get each gateway's total monthly cost, and dividing that by total volume yields an "effective rate" — the true all-in cost as a percentage, which is usually the more honest number to compare than the headline processing rate alone. Beyond the head-to-head total, the calculator solves for a break-even transaction size: the average ticket price at which the two gateways cost exactly the same, derived algebraically from the difference in their percentage rates and fixed fees.

Below that transaction size, the gateway with the lower fixed fee tends to win (fixed fees matter more on small transactions); above it, the gateway with the lower percentage rate wins (percentage fees dominate on large transactions). This is a genuinely useful number because it reframes "which gateway is cheaper" from a single yes/no answer into an understanding of how the answer would change if your typical order size shifted. A few real-world costs are deliberately out of scope here: chargeback fees, currency conversion spreads for cross-border settlement, PCI compliance overhead, and payout-timing float cost are not modeled, so a gateway that looks cheaper on paper processing fees alone could still cost more once those factors are included. Use this as a first-pass filter on rate structure, then verify against your actual contract terms before switching providers.