A routing number always has exactly 9 digits

Every routing number in the United States contains 9 digits, no more and no fewer. This nine-digit code is assigned by the American Bankers Association and identifies which bank or credit union holds your account. When you write a check or set up a direct deposit, those nine digits tell the banking system where to send or pull money.

The nine digits are always arranged the same way. The first four digits identify the Federal Reserve routing district and the specific bank. The next four digits are the ABA institution identifier unique to that bank. The last digit is a check digit — a mathematical verification that the first eight digits were entered correctly, which catches most typos before money moves.

You will see routing numbers written with or without hyphens (for example: 021000021 or 021-000-021), but the hyphens are just formatting. The actual number is always nine digits.

Key Takeaways

  • A routing number is always exactly 9 digits long, assigned by the American Bankers Association to identify your specific bank or credit union.
  • The first four digits identify the Federal Reserve district and bank, the next four are the bank's unique identifier, and the last digit verifies the number was entered correctly.
  • Hyphens sometimes appear between the digit groups for readability, but they are not part of the actual number.
  • If you enter fewer or more than 9 digits, the transaction will usually fail or be rejected as invalid.

Where the nine digits come from

The American Bankers Association created the routing number system in 1910, long before computers existed. Banks needed a standardized way to sort paper checks by hand, so the ABA assigned each bank a unique nine-digit code. That system is still in use today, even though checks are now processed by machine.

When a bank merges with another bank or changes ownership, it may keep its original routing number or receive a new one. Some large banks operate multiple routing numbers for different regions or different types of accounts. This is why you should always verify the routing number with your bank directly rather than guessing based on a previous account.

How to find your routing number

Your routing number appears in three common places. The easiest is the bottom left corner of any check you have from that account — the first nine digits printed there are your routing number. If you do not have checks, log into your bank's website or mobile app and look for account details or settings; most banks display the routing number prominently. You can also call your bank's customer service line and ask; they will confirm it over the phone.

If you are switching banks or opening a new account, do not assume your new routing number is the same as your old one. Different banks have different routing numbers, and even the same bank may use different routing numbers for different branches or account types. Always confirm with your new bank before setting up direct deposit or automatic payments.

What happens if you enter the wrong routing number

If you enter eight digits or ten digits instead of nine, the transaction will usually be rejected when ready as invalid. The check digit (the last digit) is designed to catch most single-digit errors, so if you transpose two numbers or type one wrong, the system will often catch it before the money moves.

If you enter nine digits but they belong to a different bank, the money may be sent to the wrong bank initially. The receiving bank will eventually notice the account number does not match any of their accounts and send the money back, but this can take several days. This is why it is worth taking 30 seconds to verify the routing number before you submit a transfer or set up direct deposit.

Routing numbers versus account numbers

A routing number and an account number are two different things, and you need both to move money. The routing number (9 digits) identifies the bank. The account number (usually 10 to 12 digits, but varies by bank) identifies your specific account within that bank. Together, they tell the banking system exactly where your money is and where it should go.

When you set up direct deposit for a paycheck, your employer needs both numbers. When you wire money to someone, you provide both. When you write a check, the routing number and account number are both printed on it — the routing number on the bottom left, the account number next to it.

Why banks use routing numbers instead of just names

Banks use routing numbers instead of bank names because numbers are faster and more reliable for computers to process. A computer can sort a million transactions by routing number in seconds. If the system had to match bank names instead, it would be slower and more prone to errors — what if someone typed "First National" instead of "First National Bank"?

Routing numbers also work the same way across the entire country. No matter which state you live in or which bank you use, a routing number is always nine digits. This standardization means money can move reliably between any two banks in the United States.

Frequently Asked Questions

Can a routing number have letters in it?

No. A routing number is always nine digits (0 through 9) only. If you see letters mixed in, you are looking at something other than a routing number — possibly an account number or a reference code. Routing numbers never contain letters.

Do all banks in the same state share a routing number?

No. Each bank or credit union has its own routing number, regardless of location. Two banks in the same city will have different routing numbers. Some very large banks may have multiple routing numbers for different regions or account types, but these are still unique to that bank.

If I have multiple accounts at the same bank, do they all use the same routing number?

Yes. The routing number identifies the bank, not the individual account. All your accounts at the same bank share the same routing number. The account number is what distinguishes one account from another within that bank.

What is the check digit and why does it matter?

The check digit is the last of the nine digits. It is calculated from the first eight digits using a mathematical formula, so if you type one digit wrong in the first eight, the check digit will not match and the system will reject it. This catches most typos before money is sent to the wrong place.

Can I use a routing number from an old bank account?

Only if you still bank there. If you closed that account or switched banks, that routing number belongs to your old bank and will not work for your new account. Always get the routing number from your current bank before setting up direct deposit or transfers.