Free payment processing tools for merchants
This is a free toolkit of payment processing calculators and references — chargeback ratio, refund ratio, VAMP risk, interchange rates, dispute reason codes, and MCC lookups — that help any business, from low-risk retail to high-risk merchant accounts, understand their risk metrics and keep their account healthy. No signup, no cost.
Use the calculators to benchmark your metrics against card-network monitoring thresholds, then pair them with hands-on chargeback prevention and dispute defense to protect your processing. New to the terminology? Start with the payments glossary.
Dispute reason codes
Look up what any Visa or Mastercard chargeback reason code means, its category, and how to prevent it.
Open toolVAMP risk calculator
Estimate your Visa Acquirer Monitoring Program ratio from fraud and dispute counts, and see where you stand.
Open toolChargeback ratio calculator
Calculate your monthly chargeback ratio and compare it against the card-network monitoring thresholds.
Open toolRefund ratio calculator
Work out your refund ratio and understand when it starts to draw acquirer attention.
Open toolUS interchange rates table
Reference Visa, Mastercard, Amex, and Discover interchange rates by category, searchable.
Open toolMCC directory
Search merchant category codes, their risk tier, and what each one means for your account.
Open toolPayments glossary
Plain-English definitions for the payments, underwriting, and risk terms you’ll meet along the way.
Open toolGet set up with the right account
The tools tell you where you stand — Gray Merchants gets you approved and keeps your ratios healthy across every risk level, from retail payment processing to high-risk merchant accounts. Start a free application or talk it through with a payments specialist.