Bank account numbers are almost always numbers only, but there are rare exceptions
In the United States, a standard bank account number contains only digits — no letters. Your account number is typically 8 to 12 digits long, depending on your bank. However, some banks outside the US, and a small number of specialty accounts or older systems in the US, may include letters. If you see letters in what you think is your account number, it is usually part of a different identifier, not the account number itself.
The reason banks use numbers only is practical: numbers are faster to process, harder to misread, and work the same way across all banking software. A letter can be confused with a number (the letter O looks like zero, for example), which creates room for error when money is moving between accounts.
Key Takeaways
- US bank account numbers contain only digits, typically 8 to 12 characters long.
- Letters sometimes appear in other account identifiers — like a prefix your bank assigns — but not in the account number itself.
- International bank accounts (IBAN numbers used in Europe and elsewhere) do include letters as part of their standard format.
- If you are unsure whether letters belong in your account number, ask your bank directly rather than guessing.
Where letters might appear instead of in your account number
Banks sometimes assign prefixes or codes that include letters, and these can appear on statements or in online banking next to your account number. These are not part of the account number itself. For example, a bank might label an account as "CHK-001234567" where CHK stands for checking, but only the digits 001234567 are your actual account number.
Your routing number — the nine-digit code that identifies your specific bank branch — is also numbers only. Some banks print both the routing number and account number on the bottom left of your checks in a specific format, and both are purely numeric.
If your bank sends you an IBAN (International Bank Account Number) because you are receiving money from abroad or sending it internationally, that code will include letters. An IBAN combines your country code (two letters), a check digit, your bank code, and your account number. But this is a separate identifier used only for international transfers, not your everyday US account number.
How to find your actual account number
Your account number appears in several places. The easiest is usually your online banking portal — log in and look for "Account Details" or "Account Information." Your account number will be listed there as digits only.
You can also find it on the bottom left of your checks, printed between two colons. The format is usually: routing number : account number : check number. Again, all digits.
Bank statements also show your account number at the top or in the account summary section. If you cannot find it or are unsure what you are looking at, call your bank's customer service line. They can confirm your account number in seconds and clarify what any letters or prefixes mean.
Why this matters when you are sending or receiving money
When you give someone your account number for a direct deposit or wire transfer, you should give only the digits. If you accidentally include letters or other characters, the transfer may fail or be delayed while the bank tries to figure out what you meant.
The same applies when you are setting up automatic payments or linking accounts. Banks are strict about the format: they want the account number as pure digits, nothing else. If a form rejects what you entered, double-check that you have removed any letters, spaces, or dashes.
For international transfers, the situation is different — you will be asked for an IBAN or SWIFT code, and those do include letters. But for domestic US transfers, stick to digits only.
International accounts and why they look different
If you are sending money to or receiving it from another country, you may encounter account numbers that look completely different. Many countries use IBAN numbers, which always include letters. A German IBAN, for example, looks like this: DE89370400440532013000. The DE is the country code (Germany), 89 is a check digit, and the rest identifies the bank and account.
The UK, France, Spain, and most of Europe use IBANs. Canada and Australia have their own formats. If you are working with an international account, your bank will tell you which format to use and will usually provide the number in the correct form.
For US accounts, you will never need an IBAN unless you are the one receiving money from abroad. In that case, your bank can generate an IBAN for your US account if needed, but your everyday account number remains digits only.
What to do if you are confused about your account number
The safest move is to ask your bank directly. Call the number on the back of your debit card or log into your online banking and use the chat or message feature. Tell them you want to confirm your account number and ask them to spell it out for you. They will give you the exact digits with no ambiguity.
Do not rely on guessing or on what you think you remember from an old statement. Account numbers are too important — a single wrong digit sends money to the wrong place. A 30-second phone call is worth the certainty.
Frequently Asked Questions
Can my account number have letters in it?
No, not in the US. Your account number is digits only. If you see letters, they are part of a different code your bank uses to label the account type or branch, not part of the account number itself.
What if I see letters on my check or statement next to my account number?
Those letters are usually a prefix your bank adds for internal organization — like CHK for checking or SAV for savings. When you give your account number to someone, use only the digits that follow.
Do I need an IBAN if I have a US bank account?
Only if you are receiving money from outside the US. Your bank can generate an IBAN for your account if needed, but for everyday US transfers, you use your routing number and account number (both digits).
What happens if I accidentally include letters when I give my account number?
The transfer may fail or be delayed while the bank contacts you to clarify. It is better to double-check and provide digits only the first time.
Where is the safest place to find my account number?
Your online banking portal is the most reliable source. Log in and look for Account Details or Account Information. Your bank's customer service line is also trustworthy if you cannot find it online.