ACH return reason code

R28 return code: Routing Number Check Digit Error

The routing number’s check digit is wrong.

What R28 means

R28 is the return reason code Routing Number Check Digit Error. The routing number’s check digit is wrong.

It is sent by the ACH Operator as a return entry: the original entry goes back to the ODFI with an addenda record carrying R28, and the ODFI passes the return on to the Originator.

Typical causes

The routing number’s ninth digit doesn’t match the 3-7-1 checksum of the first eight — usually a typo.

Return timeframe

Returned by the ACH Operator at its next file delivery after processing.

What the Originator can do next

Correct the routing number with the Receiver; the routing number validator checks the check digit.

How R28 appears in a NACHA file

A return is the original entry detail record (type 6) sent back with a return transaction code — 21 or 26 for a checking account, 31 or 36 for savings (21 and 31 return a credit, 26 and 36 a debit) — the original amount, and an addenda record of type 99 that carries the reason. The batch keeps the original entry’s SEC code.

Return addenda record (type 99) with R28
Positions	Field	In an R28 return
1	Record Type Code	7 (addenda)
2–3	Addenda Type Code	99 (return)
4–6	Return Reason Code	`R28`
7–21	Original Entry Trace Number	Trace number of the entry being returned
22–27	Date of Death	YYMMDD for R14 and R15; blank otherwise
28–35	Original Receiving DFI Identification	First 8 digits of the original entry’s RDFI routing number
36–79	Addenda Information	Free text from the RDFI
80–94	Trace Number	The return entry’s own trace number

To read a return file record by record, open the file in NACHA Navigator, a free sister site that parses NACHA files in your browser without uploading them.

Look up R28 from code or an AI agent

The code table on this page is the one behind the REST API and the MCP server, so a script or an AI agent gets the same answer as JSON. No key and no account.

REST · GET · no key

curl -s 'https://payopskit.com/api/v1/codes/R28?set=ach-return'

MCP · tools/call · lookup_payment_code

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "lookup_payment_code",
    "arguments": {
      "code": "R28",
      "set": "ach-return"
    }
  }
}

Response (JSON)

{
  "code": "R28",
  "set": "ach-return",
  "found": true,
  "matches": [
    {
      "set": "ach-return",
      "code": "R28",
      "name": "Routing Number Check Digit Error",
      "description": "The routing number’s check digit is wrong.",
      "details": {
        "category": "return",
        "timeframe": "Returned by the ACH Operator at its next file delivery after processing",
        "timeframeKind": "operator",
        "timeframeDays": null,
        "timeframeFrom": null,
        "account": "any",
        "accountNote": null,
        "writtenStatement": false,
        "initiatedBy": "ACH Operator",
        "note": null,
        "effectiveFrom": null,
        "upcomingChange": null,
        "caveat": null
      }
    }
  ]
}

The MCP server is at /mcp (Streamable HTTP, no key); the API and MCP docs show how to connect Claude, Cursor or VS Code.

The deadline for a settlement date: GET /api/v1/ach/return-deadline?settlement_date=2026-11-25&code=R28 or the MCP tool ach_return_deadline.

Source: Nacha Operating Rules, Appendix Four (Return Entries). The code’s title is the Rules’ own; the rest is this site’s plain-language summary. It is informational and not a substitute for the Rules, your ACH Operator’s schedule or your ODFI agreement.