A bank member number is an internal identifier your bank assigns to you as a customer, separate from your account number
When you open an account at a bank, the institution creates two different numbers to track you. Your account number identifies the specific account itself — the checking, savings, or money market account you use. Your member number (also called a customer number or client ID) identifies you as a person or business in the bank's system. A single member number can be linked to multiple accounts you hold at that bank.
The member number matters because it connects all your accounts, loans, credit cards, and services under one customer record. When you call the bank's customer service line, they ask for your member number to pull up your entire relationship with them — not just one account. It's how the bank knows that the checking account, savings account, and home equity line of credit all belong to the same person.
You'll find your member number on statements, in online banking, or by calling customer service. It's usually shorter than an account number — often 6 to 10 digits — and appears on documents like loan agreements and account opening confirmations. Different banks use different names: Chase calls it a customer ID, Bank of America uses customer number, and some credit unions label it a member number.
Key Takeaways
- A member number identifies you as a customer to your bank, while an account number identifies a specific account you hold.
- One member number can be connected to multiple accounts, loans, and services at the same bank.
- You need your member number when calling customer service, updating your profile, or managing multiple accounts.
- The member number is internal to each bank — your member number at one bank is completely different from your member number at another bank.
- Member numbers are not the same as routing numbers or account numbers and should not be shared as payment information.
How banks use your member number internally
Banks organize their customer data around the member number. When you log into online banking, the system uses your member number to display all accounts linked to your login. If you have a checking account, a savings account, and a certificate of deposit at the same bank, they're all tied to one member number in the bank's database.
Customer service representatives use the member number to see your full history with the bank — past loans, closed accounts, disputes, and service requests. This matters when you call about a problem, because the representative can see not just your current account but also whether you've had issues before or whether you're may be able to access for certain services based on your overall relationship with the bank.
The member number also appears on internal documents and in the bank's compliance records. If you're explore for a loan or a new account type, the bank uses your member number to pull your credit history and verify your identity against their existing records. It's a faster process than starting from scratch because the bank already has your information on file.
Where you'll see your member number
Your member number appears in several places. On paper statements, it's usually printed near the top or bottom, sometimes labeled as "Customer ID" or "Member ID." In online banking, you can find it in your account settings or profile section — most banks put it under "Account Information" or "My Profile." Some banks display it on the login page after you sign in.
When you open a new account, the bank sends you a welcome letter that includes your member number. If you have multiple accounts at the same bank, they all share the same member number. You can also call customer service and ask for your member number — they'll provide it after verifying your identity.
Keep your member number handy if you manage multiple accounts or if you call customer service regularly. Write it down somewhere safe, but don't share it as payment information. It's not needed for wire transfers, bill payments, or direct deposits — those require your account number and routing number instead.
Member number versus account number: what's the difference
The confusion between member number and account number is common because both appear on statements. Think of it this way: the member number is about you, and the account number is about the money. Your member number stays the same across all your accounts at one bank. Your account number changes with each account you open.
If you have a checking account and a savings account at the same bank, you have one member number but two account numbers. When you make a payment or receive a direct deposit, you provide the account number so the money goes to the right place. When you call customer service, you provide the member number so they can see all your accounts at once.
For payments and transfers, always use the account number, not the member number. The account number is what tells the banking system which specific account to move money into or out of. The member number is internal — it doesn't appear on checks, and it's not used for routing money between banks.
Why member numbers exist in banking systems
Banks use member numbers because they need a way to organize customers separately from accounts. A customer can have multiple accounts, close accounts and open new ones, and move money between institutions. The member number is a stable identifier that stays with you as long as you're a customer, even if you close an account or change account types.
From a technical standpoint, member numbers make the bank's database more efficient. Instead of storing your name, address, phone number, and contact preferences separately for each account, the bank stores that information once under your member number. Every account you hold points back to that one customer record. This is why updating your address in online banking updates it for all your accounts at once.
Member numbers also help with fraud prevention and compliance. When the bank detects suspicious activity on one account, they can quickly check your other accounts and your history with the bank. If you report fraud, the bank can flag your member number across all your accounts, not just the one that was compromised.
What you should and shouldn't do with your member number
Your member number is not sensitive information in the way your account number or Social Security number is. You can safely provide it to customer service representatives, bank employees, or when calling to check on your accounts. It's printed on statements that may be visible to household members, and it's not a secret code.
However, you should not use your member number for payments, transfers, or wire instructions. If someone asks for your member number to process a payment, that's a sign something is wrong — they should be asking for your account number and routing number instead. Never provide your member number to unknown callers or in response to unsolicited emails or texts.
Keep a record of your member number in a safe place, especially if you manage multiple accounts or if you're likely to call customer service. Having it ready when you call speeds up the process because the representative can pull up your information when ready. But don't treat it like a password or PIN — it's not meant to be secret.
Member numbers across different banks
Each bank maintains its own member numbering system. Your member number at Chase is completely different from your member number at Bank of America or Wells Fargo. The numbers don't follow a standard format — some banks use 6 digits, others use 8 or 10. There's no way to predict what your member number will be, and there's no central registry that connects member numbers across banks.
If you move accounts from one bank to another, you'll receive a new member number at the new bank. The old member number becomes inactive when you close your account. This is why it's important to update your records if you switch banks — your member number at the new institution is the one you'll use going forward.
Credit unions also use member numbers, and they function the same way as bank member numbers. The terminology is slightly different — credit unions often emphasize "member" because their customers are technically members of the cooperative — but the concept is identical. Your credit union member number identifies you in their system and connects all your accounts there.
Frequently Asked Questions
Is my member number the same as my account number?
No. Your member number identifies you as a customer, while your account number identifies a specific account. You have one member number but potentially multiple account numbers if you hold several accounts at the same bank. For payments and transfers, always use the account number.
Do I need my member number to set up direct deposit or wire transfers?
No. Direct deposits and wire transfers require your account number and routing number, not your member number. The account number tells the system which specific account to deposit money into. Your member number is internal to the bank and isn't used for moving money between institutions.
What should I do if I forget my member number?
Call your bank's customer service line and ask for it. They'll verify your identity using your name, account number, or other information and provide your member number. You can also find it on recent statements, in online banking under account settings, or on your account opening documents.
Can someone use my member number to access my account?
Your member number alone cannot be used to access your account or move money. You need your password, PIN, or other authentication to log in or authorize transactions. Your member number is not secret information, but it also doesn't grant access to your funds without additional verification.
Will my member number change if I close an account?
No. Your member number stays the same even if you close one or more accounts at the bank. It only changes if you close all your accounts and end your relationship with the bank entirely. If you reopen an account later, you may receive the same member number or a new one depending on the bank's policy.