The numbers running along the bottom of your check aren't mere decoration, each number means something. Some numbers identify your specific bank, some numbers identify your bank account, and other numbers identify the specific check. This article will outline the difference between each series of numbers and help you understand where they're located.
A bank routing number (also sometimes called "check routing numbers" or "routing transit numbers") is located on the bottom left of your check between two colons. The number has nine digits. Each bank has its own routing number, which is assigned by the American Bankers Association. When you write a check and the business deposits the check, the routing number tells the business's bank where to go and get the amount written on the check; think of it as a sort of bank return address.
Your account number is listed at the bottom of the check, in the middle, between two colons. The number of digits may vary, but account numbers typically are 10 to 12 digits long. This number will be specific only to you. Think of it as the name on the return address.
The final number is listed on the bottom of the check to the far right. It typically does not have a colon at the end. This is your check number. It will match the number listed on the top right of the check. While this number may be important to you and to your bank, in case you need to track down a specific check, it's not very important to the person who receives your check, or the person who cashes it. When you're filling out paperwork at your job for direct deposit paychecks, you'll never give your check number information. Same goes for filling out paperwork for automatic deductions; it's simply not needed.