The account number itself is usually 8 to 12 digits
Your bank account number is the core identifier your bank uses to find your account. It is typically 8 to 12 digits long, though the exact length depends on your bank. Some banks use 10 digits; others use 9 or 11. This number alone is not enough to move money — you also need the bank's routing number.
The account number appears on the bottom left of your checks, on your bank statements, and in your online banking portal. It is specific to that one account at that one bank. If you open a second checking account at the same bank, it gets a different account number.
The routing number is a separate 9-digit code
Every bank has a routing number — a 9-digit code that identifies the bank itself, not your account. When you send money via ACH transfer, wire transfer, or direct deposit, you need both the routing number and the account number. The routing number tells the payment system which bank to send the money to; the account number tells that bank which account within it should receive the funds.
Your routing number is the same for all your accounts at that bank. If you move to a different bank, you get a new routing number. You can find your routing number on the bottom left of your checks (it appears before the account number), by calling your bank, or by searching the Federal Reserve's routing number database online.
Key Takeaways
- Your account number is 8 to 12 digits and identifies your specific account; your routing number is always 9 digits and identifies your bank.
- Both numbers appear on the bottom of your checks in order: routing number first, then account number.
- You need both numbers together to set up direct deposit, ACH transfers, or wire transfers.
- The account number changes if you open a new account; the routing number stays the same for all accounts at that bank.
- Your bank statement and online banking portal both display your account number and routing number if you need to look them up.
Where to find both numbers on a check
The bottom of a check shows three groups of numbers in this order: routing number (9 digits), account number (8 to 12 digits), and check number. The routing number is printed first on the left. The account number follows immediately after. If you do not have a checkbook, you can find both numbers by logging into your online banking account or calling your bank's customer service line.
Some banks print the account number on statements and in the online portal but not on checks if you have not ordered a checkbook. In that case, your statement is the fastest way to locate it. The routing number is the same regardless of which account you are looking at, so you only need to find it once.
What other numbers appear on your account
Beyond the account number and routing number, you may see other identifiers. Your SWIFT code (also called a BIC code) is used only for international wire transfers and is typically 8 to 11 characters. Your IBAN (International Bank Account Number) is required for some international transfers and varies in length by country. Most US banks do not use IBANs for domestic transfers.
If you have a savings account, money market account, or credit card, each one gets its own account number at the same bank. The routing number stays the same across all of them. Some banks also assign you a customer ID number that groups all your accounts together, but this is for the bank's internal use and is not needed for transfers.
Why you need both numbers for transfers
When you set up direct deposit with your employer, you provide both your routing number and account number. The employer's payroll system uses the routing number to find your bank, then uses the account number to deposit your pay into the correct account. If you give only the account number, the system cannot find your bank. If you give only the routing number, the bank cannot find your account.
The same applies to ACH transfers between banks, bill pay through your bank, and peer-to-peer transfers. Wire transfers also require both numbers, though some banks ask for additional information like your full name and address to verify the transfer. If either number is wrong, the transfer will fail or go to the wrong account.
What happens if you give out your account number
Your account number alone cannot be used to withdraw money from your account without your routing number and your signature or authorization. However, you should still treat it as sensitive information. Share your account number and routing number only with people and organizations you trust — your employer for direct deposit, your bank for bill pay, or a business you are paying intentionally.
If you believe your account number has been compromised, contact your bank immediately. They can monitor your account for unauthorized activity and, if needed, close the account and issue you a new one with a new account number. Your routing number cannot be changed because it identifies your bank, not your account.
Frequently Asked Questions
Can someone withdraw money from my account if they only have my account number?
No. They would need your routing number, your authorization (signature or PIN), and often additional verification like your name and address. Your account number alone is not enough to move money. However, do not share your account number unnecessarily — always verify you are dealing with a trusted organization before providing it.
Are the numbers on my check the same as the numbers in my online banking?
Yes. The routing number and account number on your checks are identical to the ones shown in your online banking portal and on your statements. If the numbers differ, contact your bank immediately — this could indicate fraud or an error in your account setup.
Do I need a different account number if I move to a different bank?
Yes. When you open an account at a new bank, you receive a new account number and a new routing number. Your old account number at your old bank becomes inactive once you close that account. You will need to update direct deposit, bill pay, and any other automatic transfers with your new numbers.
What is the difference between my account number and my customer ID?
Your account number identifies a single account. Your customer ID (if your bank assigns one) identifies you as a customer and groups all your accounts together. You use the account number for transfers; the customer ID is mainly for the bank's records and customer service calls.
Do I need my routing number if I am transferring money within the same bank?
It depends on the bank. Some banks allow transfers between your own accounts using only the account number. Others require the routing number even for internal transfers. Check with your bank or use their online transfer tool, which will tell you what information is needed.