ABA Routing Number Validator
Validate any US bank routing number instantly — syntax, checksum, and Federal Reserve registry lookup.
Validate a Routing Number →The ABA routing number is a 9-digit code that identifies the financial institution in a US transaction. Used for wire transfers, ACH payments, and direct deposits, a single digit error can cause payment failures or delays. BankValidor checks the format, computes the weighted checksum (7-3-9 algorithm), and cross-references the Federal Reserve routing directory.
ABA Routing Number Format
ABA routing numbers follow a strict 9-digit structure defined by the American Bankers Association. The first four digits identify the Federal Reserve routing symbol, the next four identify the bank, and the ninth is a checksum digit.
How Routing Number Validation Works
Enter Routing Number
Type or paste the 9-digit ABA routing number you want to validate.
Automatic Checks
We verify format, compute the weighted checksum, and query the Federal Reserve registry.
Instant Result
Get the bank name, address, and confidence level — VALID, WARNING, or INVALID.
Frequently Asked Questions
What is an ABA routing number?
An ABA routing number is a 9-digit code identifying a US financial institution. Developed by the American Bankers Association in 1910, it is used for domestic wire transfers (Fedwire), ACH payments, and check processing. Each bank may have multiple routing numbers for different transaction types or regions.
Where do I find a routing number?
Your routing number appears on the bottom-left of a paper check, in your online banking portal, or on your bank's website. For wire transfers, banks often use a specific wire routing number that may differ from the ACH routing number.
How does the 7-3-9 checksum work?
The ABA checksum multiplies the digits by the weights 3, 7, 1, 3, 7, 1, 3, 7, 1 respectively and sums the results. If the sum is divisible by 10, the routing number is mathematically valid. BankValidor performs this check automatically.
What is the difference between an ABA routing number and a SWIFT code?
ABA routing numbers are used exclusively for domestic US transactions. SWIFT/BIC codes are used for international wire transfers. If you are sending money internationally from a US bank, you need both the ABA routing number and your bank's SWIFT code.
Ready to validate?
Enter any ABA routing number and get an instant result with bank name and registry status.
Validate a Routing Number →