Calculate US routing check digits.
Initialising algorithm engine for ABA Routing Number Calculator...
How ABA Routing Number Calculator Works?
The ABA Routing Number Calculator works by multiplying the first 8 digits of a routing transit number by the repeating weights 3, 7, 1, summing the products, and appending the digit that brings the total to a multiple of 10.
- 1Enter the first 8 digits of the 9-digit American Bankers Association (ABA) routing number.
- 2Multiply digits 1, 4, and 7 by 3; digits 2, 5, and 8 by 7; digits 3 and 6 by 1.
- 3Add the 8 products.
- 4Compute the 9th digit as (10 − (S mod 10)) mod 10.
ABA Routing Number Calculator Formula
The ABA routing number formula is 3(d₁ + d₄ + d₇) + 7(d₂ + d₅ + d₈) + (d₃ + d₆ + d₉) ≡ 0 (mod 10).
S = 3(d₁ + d₄ + d₇) + 7(d₂ + d₅ + d₈) + 1(d₃ + d₆) d₉ = (10 − (S mod 10)) mod 10
d₁…d₄are the Federal Reserve routing symbol.d₅…d₈are the institution identifier.
0 × 3 = 0 2 × 7 = 14 1 × 1 = 1 0 × 3 = 0 0 × 7 = 0 0 × 1 = 0 0 × 3 = 0 2 × 7 = 14 S = 29 Check = 1 Routing number = 021000021
ABA Routing Number Calculator Conversion Table
The ABA conversion table lists well-known routing number formats with their computed 9th digit.
| First 8 digits | Federal Reserve district | Weighted sum | Check digit | Routing number |
|---|---|---|---|---|
| 02100002 | 2 – New York | 29 | 1 | 021000021 |
| 01100001 | 1 – Boston | 15 | 5 | 011000015 |
| 12100035 | 12 – San Francisco | 62 | 8 | 121000358 |
| 07100001 | 7 – Chicago | 57 | 3 | 071000013 |
| 26107398 | 6 – Atlanta (thrift) | 184 | 6 | 261073986 |
| 32207056 | 12 – San Francisco (thrift) | 131 | 9 | 322070569 |
What is ABA Routing Number Calculator?
An ABA Routing Number Calculator is a tool that computes or checks the 9th digit of a US bank routing transit number. Routing numbers identify financial institutions for ACH transfers, wire transfers, and cheques.
The first 2 digits show the Federal Reserve district (01–12), thrift range (21–32), or special use. The 3-7-1 weights detect all single-digit errors and most adjacent transpositions.
What are the uses of ABA Routing Number Calculator?
There are 4 main uses of the ABA Routing Number Calculator, including ACH setup, cheque processing, and payroll forms.
- ACH setup: Businesses check routing numbers before creating ACH payment files.
- Cheque processing: Banks validate the MICR line on scanned cheques.
- Payroll forms: Employers catch typos in direct deposit forms.
- Developer validation: Apps reject invalid routing numbers on entry.