ABA routing number validator
Check a US bank routing number before you save it in SAP Business One or send a payment file: 9 digits, the 3-7-1 check digit and the Federal Reserve district.
Tool
Format and check digit only. This is not a bank lookup: it does not confirm that the bank exists, is active, accepts ACH or wires, or that any account exists.
This free tool checks the format and check digit of a US routing number only. It is not a bank lookup and does not confirm that a bank, branch or account exists, is active or accepts a given payment type. Always confirm bank details with the bank before sending money. Kodenova is an independent SAP Business One, ERP and AI development studio; SAP and SAP Business One are trademarks of SAP SE.
How the routing number check digit works
The ninth digit is a check digit. It is chosen so that a weighted sum of all nine digits ends in zero. The weights repeat 3, 7, 1 from left to right.
Worked example, using a number printed in the Federal Reserve’s routing key (Treasury checks): 0000-0051-8
| Position | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
|---|---|---|---|---|---|---|---|---|---|
| Digit | 0 | 0 | 0 | 0 | 0 | 0 | 5 | 1 | 8 |
| Weight | 3 | 7 | 1 | 3 | 7 | 1 | 3 | 7 | 1 |
| Product | 0 | 0 | 0 | 0 | 0 | 0 | 15 | 7 | 8 |
15 + 7 + 8 = 30, a multiple of 10, so the check digit is right. Change any single digit and the sum no longer ends in zero, which is why the check catches most typing mistakes.
To find a missing ninth digit: add the weighted first eight digits, then take the amount needed to reach the next multiple of 10.
What the first two digits mean
The Federal Reserve’s routing key and 12 CFR Part 229, Appendix A, explain the first digits:
| First two digits | Meaning |
|---|---|
| 01 to 12 | Bank in Federal Reserve District 1 (Boston) to 12 (San Francisco) |
| 21 to 32 | Thrift or credit union in the same district (subtract 20: 21 = Boston, 32 = San Francisco) |
| 00 | Used in the Federal Reserve key for U.S. Treasury checks, postal money orders and savings bonds |
| 80 | Appears in the Federal Reserve key for a few specific numbers; the tool does not label it further |
| 61 to 72 | Outside the check routing ranges in the Federal Reserve key; other tools call these electronic-only identifiers, which we could not confirm from an official source |
| Anything else | Not used by these ranges |
The 12 districts: 01 Boston, 02 New York, 03 Philadelphia, 04 Cleveland, 05 Richmond, 06 Atlanta, 07 Chicago, 08 St. Louis, 09 Minneapolis, 10 Kansas City, 11 Dallas, 12 San Francisco.
The district tells you where the routing number was assigned. It does not tell you where the customer lives or where the branch is today.
What this validator does not check
- Whether the bank exists, merged or closed.
- Whether the routing number is enabled for ACH, wires or real-time payments. Banks often publish different numbers for wires and ACH.
- Whether an account number exists or belongs to the name you were given.
For those, ask the bank, or use the official Federal Reserve E-Payments Routing Directory, which is a separate service. Never treat a passing check digit as approval to pay.
Routing number, account number, SWIFT and IBAN
The routing number identifies the bank. The account number identifies the account at that bank and has no national check digit. US banks do not use IBAN. For international wires into the US, the sending bank usually asks for the SWIFT/BIC code as well as the routing number.
Importing US bank data into SAP Business One
This is a short guide to where routing numbers live in SAP Business One and how bank statements come back in. Menu paths can differ slightly by version and localization.
1. Define the bank
Go to Administration > Setup > Banking > Banks. Create one record per bank with country United States. In the US localization the Bank Code field normally holds the 9-digit ABA routing number. Validate the number before you save it: a typo here is copied into every payment that uses the bank.
2. Set up your house bank accounts
Go to Administration > Setup > Banking > House Bank Accounts. For each of your company’s accounts, pick the bank, enter the account number and branch, and link the G/L account that the bank postings use. Set the default house bank in Administration > System Initialization > Company Details if your version shows the house bank fields there.
3. Add vendor and customer bank details
In the Business Partner Master Data, open the Payment Terms tab and add the partner’s bank accounts (bank, account number, and the routing number through the bank code). Outgoing payment runs from the Payment Wizard read these details, so a wrong routing number here means a returned payment later.
4. Import bank statements
Go to Banking > Bank Statements and External Reconciliations > Bank Statement Processing. Depending on your version and localization, you import the bank’s file (for example BAI2 or MT940) with a format defined in the Electronic File Manager, or you enter lines manually. Each statement line can then be matched to open payments and posted.
5. Reconcile
Use External Reconciliation to match the imported bank lines against the G/L account of the house bank. Investigate unmatched lines before you close the period.
Good practice: run every new routing number through a check-digit validator before it reaches the Banks or Business Partner screens, and keep a change log for bank detail edits, because changed bank details are a common fraud route.
Need custom bank imports, payment files or a check inside SAP Business One? See SAP Business One development.
Related pages
This free tool checks the format and check digit of a US routing number only. It is not a bank lookup and does not confirm that a bank, branch or account exists, is active or accepts a given payment type. Always confirm bank details with the bank before sending money. Kodenova is an independent SAP Business One, ERP and AI development studio; SAP and SAP Business One are trademarks of SAP SE.
Three steps, no signup
Paste the routing number
Spaces and dashes are ignored, so 0110-0001-5 and 011000015 both work.
We check the digits
Length, the 3-7-1 check digit and the first two digits are checked in your browser.
Save clean bank data
Use the result before you create the house bank or the business partner bank account in SAP Business One.
Questions about this tool
How do I check if a routing number is valid?
Enter the 9 digits in the tool. It multiplies them by 3, 7, 1, 3, 7, 1, 3, 7, 1 and checks that the total is a multiple of 10, then reads the first two digits to show the Federal Reserve district. A pass means the number is well formed, not that the bank confirmed it.
Does a valid check digit mean the bank account exists?
No. The check digit only shows that the nine digits are consistent with each other. It cannot tell you whether the bank still exists, accepts ACH or wires, or holds the account you were given. Confirm bank details with the bank or through a verified call before you send money.
What do the first two digits of a routing number mean?
01 to 12 are the twelve Federal Reserve districts, from Boston to San Francisco. 21 to 32 are thrifts and credit unions in the same districts, so subtract 20. 00 is used for U.S. Treasury checks, postal money orders and savings bonds in the Federal Reserve's routing key.
Why do ACH and wire routing numbers differ?
Many banks publish one routing number for ACH and checks and another for wire transfers, often because wires are processed by a different office or a correspondent bank. Both can pass the check digit test, so ask the bank which number belongs to which payment type before you save it in your ERP.
Where is the routing number stored in SAP Business One?
In the US localization the routing number normally goes in the Bank Code of the bank record under Administration, Setup, Banking, Banks. House bank accounts and business partner bank accounts then point to that bank. Field names can vary by version and localization, so check yours before importing data.
Is my routing number sent anywhere?
No. The calculation runs in your browser and the number is not sent to Kodenova or anyone else. The tool has no bank database and does not look anything up; it only applies the published check digit rule and the district table to the digits you enter.
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