Mastercard Reason Code 4831: Transaction Amount Differs

What Mastercard reason code 4831 means

4831 is a legacy processing-error code. The cardholder agrees they made the purchase, but says the amount charged doesn’t match the amount they agreed to: the total on the receipt, the quote they accepted, or the price at checkout.

Mastercard now handles this claim as the “transaction amount differs” sub-scenario of 4834 Point-of-Interaction Error. Your processor may still show 4831. The evidence is the same either way.

4831 vs similar codes

The distinction matters because a one-click upsell can be framed either way: as a higher amount on one transaction (amount differs) or as a separate unauthorized charge (fraud). Your evidence of the customer’s acceptance answers both.

Common causes

• Post-purchase upsells added to the original capture, so the final charge exceeds the checkout total
• Shipping or tax recalculated after checkout
• Orders edited by support (items added or swapped) without written confirmation of the new price
• Restaurant or hospitality tip adjustments that don’t match the signed receipt
• Estimates for services that ended up higher than quoted
• Keying errors, such as an extra zero on a manually entered amount

Evidence that wins a 4831 dispute

1. The agreed amount: checkout page or order confirmation email, signed receipt, or the quote the customer accepted.
2. The charged amount, showing it matches.
3. Consent to any change: a timestamped upsell acceptance, an email approving a revised quote, or a signed tip line.
4. Itemization showing how the total was calculated, including shipping, tax and add-ons.
5. Partial-capture records if the order shipped in pieces, showing the sum of captures doesn’t exceed the authorized total.

For upsell disputes, the strongest single piece is the acceptance screen showing the new total and the customer’s click.

How to prevent 4831 chargebacks

• Show the full new total, not just the add-on price, when a customer accepts an upsell, and email a revised confirmation.
• Lock the checkout total. If something must change after checkout, get written approval before you capture.
• Capture tips and adjustments from the signed or confirmed amount only.
• Send itemized receipts so the customer can reconcile the statement line.

Should you fight or accept?

Fight when you can show the cardholder agreed to the exact amount charged, including any later change. These disputes rest on documents and are very winnable.

Accept when the charge exceeds what the customer approved, for example a shipping recalculation they never saw. This type of chargeback is usually for the difference rather than the whole order, so check the disputed amount before deciding, and fix the step that changed the total. For general refund-vs-dispute tradeoffs, see chargeback vs refund.