On a standard personal check, the check number sits in the upper right corner, just above or beside the date line. It’s a short sequence, usually three or four digits, and new checkbooks often start the numbering at 101. The same number is printed again at the far right end of the coded line running along the bottom edge of the check, where it is the shortest group of digits.1American Bankers Association. ABA Routing Number
The two printed copies should match. If they don’t, the bank may flag the check for review when it’s processed. Checking that both numbers agree is also a quick way to confirm you’re reading the check number itself and not one of the longer numbers next to it.
Telling the Check Number Apart From the Routing and Account Numbers
The row of numbers along the bottom of a check is printed in magnetic ink and is called the MICR line. Three groups of digits sit on it, separated by small bracket-like symbols:
- The routing number is on the far left and is always nine digits. It identifies the bank that holds the account and is bracketed by a symbol that looks like a vertical line with two dots on either side.1American Bankers Association. ABA Routing Number
- The account number sits in the middle. It commonly runs eight to twelve digits, though some banks use longer sequences, and it’s bracketed by a different symbol with a single dot.
- The check number is on the far right. It is almost always the shortest group on the line, and it matches the number in the upper right corner of the check.
Length is the easiest tell. If one group of numbers is clearly shorter than the others, that’s the check number. The nine-digit block on the left is the routing number, and the medium-length block in the middle is the account number.
Some business checks carry an extra group of digits on the far left, before the routing number. That is an auxiliary number used by the company’s internal accounting system. It isn’t part of your routing or account information, and it isn’t the check number either.
Business Checks, Starter Checks, and Cashier’s Checks
Business checks follow the same general layout, but the check number can run longer, up to ten digits in some cases. Companies that process high volumes of payments use longer sequences to keep their accounting organized. On voucher-style or three-per-page business checks, each individual check portion still shows its own check number in the upper right corner, with a matching copy on the MICR line below.
Starter checks are the temporary checks a bank hands you when you open a new account. They don’t always carry a printed check number, and when they do it often begins at 101. Some merchants decline starter checks for that reason, since the missing check number, name, and address make verification harder. If you need to pay by check before your personalized supply arrives, ask the recipient first whether they’ll accept one.
Cashier’s checks and money orders don’t use the term “check number” at all. The identifying number is called a serial number and is printed in a larger or bolder font near the top of the document. The MICR line at the bottom still carries an encoded number, but the serial number at the top is the reference the issuing bank will ask for if you need to trace the item or request a stop payment.
When You’ll Actually Need the Check Number
For many everyday tasks, you don’t need the check number. Setting up direct deposit or online bill pay only requires your routing and account numbers, which is why a voided check works for sharing that information with an employer or billing company.
You will need the check number in a few specific situations:
- Stopping payment on a check you’ve written. Your bank will ask for the check number along with the exact dollar amount, because under the Uniform Commercial Code you have to describe the check in enough detail for the bank to identify and intercept it before it clears.2Legal Information Institute. UCC 4-403 – Customers Right to Stop Payment Burden of Proof of Loss
- Documenting a business expense for taxes. If you no longer have the canceled check, the IRS will accept a bank statement as proof of payment, but only if the statement shows the check number, the dollar amount, the payee, and the date the check posted. Logging check numbers in your register as you go makes matching expenses to your statements much easier at tax time.3Internal Revenue Service. Publication 583 – Starting a Business and Keeping Records
- Disputing a check that was processed incorrectly. Having the check number lets you point your bank at the exact transaction when you file a claim.4eCFR. 12 CFR 229.54 – Expedited Recredit for Consumers
- Mobile deposit. When you deposit a check through a banking app, the full MICR line, including the check number, has to be clearly visible. Banks use the check number together with the routing and account numbers to catch duplicate deposits, so if the bottom edge of the image is cut off or blurry the app will reject it.