Two Numbers, Two Purposes
If you've ever set up a direct deposit, paid a bill online, or filled out a US bank form, you've encountered a routing number and an account number. These two numbers work together to identify both the financial institution and the specific account within it — but they serve very different roles.
What Is a Routing Number?
A routing number (also called an ABA routing number or ABA transit number) is a 9-digit code that identifies a specific bank or credit union in the United States. It was developed by the American Bankers Association (ABA) in 1910.
Think of the routing number as the bank's address — it tells the payment system which financial institution to direct the funds to. Every US bank has at least one routing number, and large banks may have several (different numbers for different states or transaction types).
What Is a Routing Number Used For?
- Setting up direct deposit of your paycheck
- Authorising ACH (Automated Clearing House) payments
- Setting up automatic bill payments
- Sending or receiving domestic wire transfers
- Writing paper checks
What Is an Account Number?
An account number is a unique identifier assigned by your bank specifically to your account. It typically ranges from 8 to 17 digits in length, depending on the bank.
While a routing number identifies the bank, the account number pinpoints the exact account within that bank. Two customers at the same bank will have the same routing number but different account numbers.
What Is an Account Number Used For?
- Identifying your specific account for deposits and withdrawals
- Appearing on checks alongside the routing number
- Linking external accounts or payment services to your bank
- Receiving international wire transfers (along with the bank's SWIFT code)
Routing Number vs Account Number: Side-by-Side
| Feature | Routing Number | Account Number |
|---|---|---|
| Length | Always 9 digits | 8–17 digits |
| What it identifies | The bank/financial institution | Your specific account |
| Unique to you? | No — shared by all customers of the bank | Yes — unique to your account |
| Found on a check | Bottom-left (first set of numbers) | Bottom-centre (second set) |
| Used for international transfers? | No (use SWIFT/BIC instead) | Yes (alongside SWIFT code) |
Where to Find Your Routing and Account Numbers
The easiest places to locate these numbers are:
- On a paper check — the routing number is the first 9 digits on the bottom-left, followed by your account number, then the check number.
- In your online banking app — log in and look under account details or settings.
- On your bank statement — account details are usually printed at the top.
- By contacting your bank — customer service can confirm both numbers.
Are These Numbers Safe to Share?
Routing and account numbers are routinely shared for legitimate purposes like direct deposits and bill payments. However, be cautious about who you share them with — together, these numbers can be used to set up unauthorized debits. Only provide them to trusted institutions, and never share them in response to unsolicited requests.
What About Outside the US?
Other countries use different systems. In the UK, a sort code plays the role of the routing number. In Europe and many other regions, an IBAN combines both the bank identifier and account number into a single standardised string. For international US transfers, you'll pair your account number with your bank's SWIFT/BIC code rather than the routing number.