Bank account numbers are usually between 8 and 17 digits long, depending on your bank and the type of account

There is no single standard length for a bank account number in the United States. Each bank sets its own format, so your account number might be 8 digits, 12 digits, or somewhere in between. The length does not tell you anything about the account itself — a longer number does not mean a bigger account or a different type of account.

When you need your account number for a payment or transfer, you will find it on the bottom left of your checks, in your online banking portal, on your bank statement, or by calling your bank's customer service line. The bank will always tell you the correct number if you ask.

Key Takeaways

  • Account numbers range from 8 to 17 digits depending on which bank holds your account, not on the type of account you have.
  • Your account number appears on the bottom left of your checks, in your online banking login, and on statements your bank sends you.
  • The routing number (which comes before your account number on a check) is always 9 digits, but your account number length varies by bank.
  • When you give out your account number, you should always pair it with your routing number so the receiving bank knows which bank to contact.

Where to find your account number

The easiest place to look is the bottom of a check. On the left side, after a colon, you will see your routing number (9 digits), then your account number. Count the digits after the routing number — that is your account number length.

If you do not have checks, log into your online banking account. Most banks display your account number on the dashboard or in an account details section. You can also call your bank's customer service number (on the back of your debit card) and ask them to read it to you. They will verify your identity first.

Why banks use different lengths

Banks developed their account numbering systems at different times, often before there was any national standard. Some older banks use shorter numbers because they were designed when banks had fewer customers. Newer banks or banks that merged with others sometimes use longer numbers to avoid running out of possible combinations.

The length also does not change if you move money between accounts at the same bank. A savings account and a checking account at the same bank will have different account numbers, but they might be the same length or different lengths — there is no pattern.

How account numbers work with routing numbers

Your account number alone is not enough information for a transfer or payment. You also need your routing number, which is always 9 digits and identifies which bank holds your account. Together, the routing number and account number tell the sending bank exactly where to send money.

When you set up a direct deposit, make an online payment, or send money via wire transfer, you will need to provide both numbers. The routing number goes first, then the account number. If you give only the account number, the receiving bank will not know which bank to contact.

Account numbers on checks versus online

The account number printed on your checks is the same as the one in your online banking account — they are not different numbers. Banks print it on checks so you can share it with people who need to send you money or so you can reference it when you call customer service.

Some banks print the account number in a different order or format on statements than on checks, but it is still the same account number. If you are unsure, compare the numbers or call your bank to confirm.

What happens if you give out your account number

Sharing your account number alone is generally low risk because someone also needs your routing number to transfer money out of your account. However, you should still be cautious about who you give it to. Only provide your account number to people or organizations you trust, such as your employer (for direct deposit), your landlord (for rent payments), or established companies you do business with.

If you are concerned that your account number has been compromised, contact your bank when ready. They can monitor your account for unauthorized activity and, if needed, issue you a new account number.

Frequently Asked Questions

Is there a maximum or minimum length for account numbers?

In practice, account numbers range from 8 to 17 digits, but there is no federal rule that sets a hard minimum or maximum. Each bank chooses its own system. If your bank's account number seems unusually short or long, it is still correct — just call your bank if you want to confirm.

Do all accounts at the same bank have the same number of digits?

Usually yes, but not always. Most banks use the same length for all their checking and savings accounts, but some banks have different formats for different account types or for accounts opened in different years. Your bank can tell you if this applies to you.

Can I change my account number?

You cannot change your account number yourself, but your bank can issue you a new one if you ask. This is sometimes done if you are concerned about fraud or if you want a fresh start. Be aware that you will need to update your account number with anyone who has it on file, such as your employer or creditors.

What if I only have part of my account number?

Call your bank with your name, address, and identification. They will verify who you are and provide your full account number. Never guess or try to fill in missing digits — an incorrect number could send money to the wrong account.

Are account numbers the same across different banks?

No. If you have accounts at two different banks, each account will have a different number and a different routing number. The numbers are not shared between banks, so you need to keep track of which number belongs to which bank.