Processing fees can increase month-to-month even when nothing about your business seems to have changed. This guide explains the most common reasons your effective rate may vary — and what to look for when it does.
Last reviewed: July 4, 2026 · Editorial policy
Quick Answer
Processing fees change because of: (1) card network interchange rate adjustments, (2) shifts in your customers' card mix, (3) more transactions being downgraded on tiered pricing, (4) processor markup changes, (5) new or increased monthly fees, or (6) risk reviews. Calculating your effective rate each month helps you detect changes early and trace their source.
Visa and Mastercard adjust interchange rates periodically — historically twice per year. When these changes take effect, your effective rate under interchange-plus or membership pricing changes accordingly, even if your processor's markup stays the same. On flat-rate pricing, your rate doesn't change unless your processor adjusts their flat rate.
Your card mix is the distribution of card types your customers use. Different card types carry different interchange rates — debit cards and basic credit cards typically have lower rates than premium rewards cards or corporate cards. If your customer demographic shifts (seasonal changes, new marketing channels, B2B sales), your average interchange cost can change significantly.
On tiered pricing, transactions can be downgraded to higher-cost tiers for various reasons: accepting more reward cards, manually keying more transactions, delayed batch settlement, or processing card-not-present transactions. Increases in non-qualified or mid-qualified volume directly raise your effective rate.
Some processors increase their markup over time. Contract terms govern how much notice is required and under what conditions rates can change. Some contracts allow rate increases with 30 days' notice; others lock in rates for a term. Review your contract's rate change provisions.
Processors sometimes add new fees or increase existing ones — PCI compliance fees, gateway fees, statement fees. These may be introduced quietly or with minimal notice depending on your contract terms.
If your chargeback rate increases, your processing volume changes significantly from your original application, or your business type triggers a risk review, your processor may adjust your pricing as a risk management measure. This is more common for businesses that have seen elevated chargebacks or dispute activity.
If your monthly volume drops below a minimum fee threshold, you may be charged a monthly minimum fee even if you process fewer transactions. This effectively increases your effective rate in slower months.
Educational content. Fee change rules vary by processor and contract. Interchange rate adjustment schedules are published by Visa and Mastercard and can be consulted directly. ProcessorFit does not guarantee any specific rate outcome. Editorial policy.
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Verification note
Interchange rate changes are announced by Visa and Mastercard periodically. Processor markup changes are governed by individual merchant agreements. Verify current terms with your processor.