What Is An ABA Routing
Number Check Digit?
A check digit is a form of
redundancy check used for error detection for many algorithm
generated numbers such as ABA Routing Numbers, Credit Card
Numbers, etc. but for our purposes here, refers to ABA Routing
Numbers created by the American Banking Association.
Basically, it is the decimal
equivalent of a binary checksum and really has nothing to do
with a written Check at all.
It consists of a single digit
computed from the other digits in the ABA
Routing Number.
Often, the last number of a 9 digit
ABA Routing Number is missing, either cut off from electronic
transmission, or missed during entering.
There is a special algorithm you can
use to identify that missing number by simply using the first 8
digits of a known ABA Routing Number.
How To Calculate Missing Check Digit
From An ABA Routing Number.
To calculate
bank routing check digit (digit #9 is used to validate
8-digit bank routing (ABA) number) -
A check digit is a digit added to a number at the end validates
the authenticity of the number. A simple algorithm is applied to
the other digits of the number which yields the check digit. By
running the algorithm, and comparing the check digit you get
from the algorithm with the check digit encoded with the routing
number, you can verify that you have correctly read all of the
digits and that they make a valid combination.
Checks typically bear a nine-digit ABA routing number printed in
the bottom left-hand corner. In general, the first four digits
are a Federal Reserve routing symbol, identifying which of the
twelve Federal Reserve districts the check was printed in (and a
city within that district).
The next four
digits are an ABA institution identifier which designates the
bank on which the check is drawn, and the last number is a check
digit.
http://www.routingchecker.com
provides a tool for locating a missing or erroneous check
digits, or validating a routing number through an online
validation form. Also available is an option to download all
21,000+ ACH Routing Numbers and the associated Bank information.
Click
Here to find out more.
