Banking · Routing numbers
Routing number decoder for the Federal Reserve district and checksum.
Type a nine-digit US routing number to see what its digits say about the Federal Reserve district, whether the prefix marks a thrift, and whether the check digit works.
Short answer: digits 1–2 give the Federal Reserve district (01–12), +20 means a thrift, and the whole number must satisfy 3(d1+d4+d7) + 7(d2+d5+d8) + (d3+d6+d9) divisible by 10. It will not name the bank.
Decode a routing number
Result
- Enter nine digits to decode.
How a routing number is built
Appendix A to Regulation CC says the first four digits are the “Federal Reserve routing symbol” and the first two identify the Federal Reserve District. 01 is the First District (Boston) and 12 the Twelfth (San Francisco). Adding 2 to the first digit denotes a thrift: 21 is a thrift in the First District, 32 in the Twelfth. The ninth digit is a check digit.
The 3-7-1 check
Multiply digits 1, 4, 7 by 3, digits 2, 5, 8 by 7 and digits 3, 6, 9 by 1. If the total is a multiple of 10 the number is well formed. This catches most single-digit typos and swapped neighbours, and says nothing about whether an account exists.
What this page leaves out
Prefixes outside 01–12 and 21–32 (for example those used for electronic-only routing) are not defined in Appendix A, so this page reports them as “not in Appendix A” rather than guessing. The Fed’s E-Payments Routing Directory requires you to accept terms that prohibit using its data for commercial gain, so no bank list is reproduced here. To find your own bank’s number, use its online account, a printed check (the first nine-digit group at the bottom left), or the bank’s own routing page, because some banks list different numbers by state or payment type.
Frequently asked questions
What do the first two digits of a routing number mean?
Under 12 CFR Part 229 Appendix A, the first two digits identify the Federal Reserve District of the bank: 01 is Boston and 12 is San Francisco. Adding 2 to the first digit marks a thrift institution, so 21 is a thrift in the First District and 32 a thrift in the Twelfth.
Does this tell me which bank owns a routing number?
No. The nine digits carry a district, a processing-center code and an institution number, but the owner name comes only from the Federal Reserve E-Payments Routing Directory, whose terms of use bar reuse for commercial gain. This page links to it and does not copy it.
Is a routing number that passes the checksum real?
Not necessarily. The check digit only catches typos: about one random nine-digit number in ten passes. Confirm the number with the bank or in the Fed directory before sending money.
What are the first four digits called?
The Federal Reserve routing symbol, per the same Appendix A. The last digit is the check digit.
Why does my bank list different routing numbers for wires and ACH?
Some banks publish separate numbers by payment type or account-opening state. This page cannot tell you which applies. Use the number on your bank's own routing page or your online account.
Format check only — not financial advice
This tool checks number structure. It does not confirm that a routing number is active, who owns it, or that it suits a given payment. Confirm with your bank before sending funds. Page reviewed November 2, 2026.