A payer’s RTN, short for routing transit number, is the nine-digit code that identifies the bank or credit union being debited in a payment. You’ll find it printed along the bottom-left of a paper check, listed in your bank’s mobile app or website, and shown on your monthly statements. Every U.S. financial institution that processes checks or electronic payments has at least one, and you’ll be asked for it anytime you set up direct deposit, pay a bill electronically, or send an ACH transfer.
Where to Find Your Routing Number
On a paper check, the routing number sits on the MICR line at the bottom-left edge, printed in magnetic ink. It’s always nine digits, bracketed by a pair of transit symbols that look like a vertical line with two dots. Read left to right and stop after nine digits. The string to the right is your account number (and, on many checks, the check number), and the account number’s length varies by bank.
Most people don’t keep a checkbook around anymore. A few other places to look:
- Your bank’s mobile app or online banking portal, in the account details screen.
- Your bank’s public website, often on a help or FAQ page. Searching the bank’s name plus “routing number” usually lands you there.
- Monthly statements, paper or electronic, near the account information header.
- Customer service. Call the number on the back of your debit card and ask which routing number applies to your transaction.
Your Bank May Have More Than One
This is where payments go wrong. The routing number printed on your checks isn’t necessarily the one you need for every type of transaction. Banks often maintain separate routing numbers for paper checks, ACH electronic transfers, and wire transfers, because these transactions travel through different clearing networks. ACH payments move in batches through the Automated Clearing House. Wire transfers settle individually and in near-real time. Each path may use a different number at the same bank.
Confirm with your bank which routing number applies before you set up a transfer. It’s especially worth checking for wires, since domestic wire transfers commonly cost $25 to $30 in bank fees, and a rejected wire means paying that fee again.
What You’ll Need Alongside the RTN
The routing number tells the system which bank. You also need your account number, which tells the system which account inside that bank. These two pieces travel together on nearly every electronic payment form. The account number is the longer string and varies in length by institution.
Payment forms also want the account holder’s name as it appears on the bank’s records. A spelling difference, a missing middle initial, or a nickname instead of a legal name can trigger a rejection or a fraud flag. If a payment keeps failing with no obvious cause, name formatting is often the reason.
The check digit built into every routing number offers one more layer of protection. The ninth digit is calculated from the first eight, so if you mistype any single digit the system catches it and rejects the number before money moves. That doesn’t help if you’ve entered a valid routing number for the wrong network, but it does stop most typos cold.
When a U.S. Routing Number Won’t Work
Routing transit numbers only work for domestic U.S. transactions. If you’re sending money to another country or receiving it from abroad, you’ll need a SWIFT code (also called a BIC) instead. SWIFT codes are 8 to 11 alphanumeric characters that identify banks globally. Your bank can give you its SWIFT code, and the recipient’s bank will have one too.
For federal tax payments through IRS Direct Pay or EFTPS, use your bank’s ACH routing number rather than any wire or international code. The IRS treats these as standard ACH debits and doesn’t accept SWIFT codes for electronic tax payments.1Internal Revenue Service. Direct Pay Help
Keeping Your Routing and Account Numbers Safe
Your routing number by itself isn’t particularly sensitive. It’s printed on every check you hand out and often published on your bank’s website. The risk starts when someone has your routing number and your account number together. With both, a fraudster can initiate unauthorized ACH debits by posing as a merchant or other entity you’ve authorized. Early fraudulent debits are often small amounts, designed to avoid attention.
Federal law caps your losses, but the caps depend on how fast you report. Under the Electronic Fund Transfer Act, report an unauthorized transfer within two business days of discovering it, and your maximum liability is $50.2Office of the Law Revision Counsel. 15 USC 1693g – Consumer Liability Wait longer than two days but report within 60 days of receiving the statement that shows the transfer, and your exposure rises to $500.3eCFR. 12 CFR 1005.6 – Liability of Consumer for Unauthorized Transfers Miss the 60-day window and you can be liable for every unauthorized transfer that happens after the deadline passed, with no cap.
So review your statements every month. Flag anything you didn’t authorize and report it immediately. Many banks offer ACH debit filters or blocks that let you pre-approve which companies can pull from your account, stopping unauthorized debits before they clear. If you’ve shared your account details with someone you shouldn’t have, ask the bank to change the account number rather than waiting to see what happens.