The routing number can have two forms—fraction form and MICR (magnetic ink character recognition) form. Essentially, they contain the same information. MICR form is the more commonly used form, and it is very rare to see the fraction form as of 2020.
Within the 4 digit Federal Reserve Routing Symbol, the first two digits can only be 00 - 12, 21 - 32, 61 - 72, or 80. Within these ranges:
- 21 - 32 are assigned to thrift institutions only, such as credit unions and savings banks.
- 61 - 72 are special purpose numbers for non-bank payment processors and clearinghouses and are termed Electronic Transaction Identifiers (ETIs).
- 80 is for traveler's checks.
- Aside from 80, the first two digits can be associated with the 12 Federal Reserve Banks.
Check Digit Validation
The check digit is the ninth digit of the routing number and must meet the following condition. This condition is mainly intended to reduce misrouting errors typically due to input errors.
For example:
111000038 is the routing number of the Federal Reserve Bank in Minneapolis.
3(1+0+0) + 7(1+0+3) + (1+0+8) = 40
40 mod 10 is 0, so the check digit condition was met.