Banks have a 9 digit routing number that consists of the 8-digit bank number followed by the checksum digit.  When entering the first 8 digits, the 9th digit will calculate as a check digit.  It is not necessary to enter the 9th digit in the DFI ID field.  Fundware will calculate the check digit and it will appear in the EFT transmittal file.

How is the check digit calculated?  How can I prove the check digit (9th digit) is correct in my PY2 or PYN file?

The Check Digit is computed using Modulus 10 as follows:
1. Multiply each digit in the Transit Routing/ABA (T/R) Number by a weighting factor.  The weighting factors for each digit are:
Position:     1     2     3     4     5     6     7     8

Weights:     3     7     1     3     7     1     3     7

2.  Add the results of the eight multiplications.

3.  Subtract the sum from the next highest multiple of 10.  The result is the Check Digit.  For example:

T/R Number          1     1     1     0     0     0     0      2
Multiply by               3     7     1     3     7     1     3      7
__________________________________________________
T/R Number x weight     3     7     1     0     0     0     0     14

Sum = 25 (3+7+1+0+0+0+0+14)
Check Digit = 5 (30 minus 25; 30 is the next highest multiple of 10 above the sum of 25)