Validate a US routing number by its check digit, see the Federal Reserve district and class, and generate test numbers in bulk.
The routing number (ABA RTN) has 9 digits in three parts: a 4-digit Federal Reserve routing symbol, a 4-digit institution identifier and a check digit. The first two digits give the class and district: 01 to 12 are banks in the 12 Fed districts (01 Boston, 02 New York, up to 12 San Francisco), 21 to 32 are thrifts and credit unions (the district plus 20), 61 to 72 are electronic identifiers (the district plus 60), 00 is the government and 80 is for traveler's checks. The last digit comes from a weighted sum: 3 times digits 1, 4 and 7, plus 7 times digits 2, 5 and 8, plus digits 3, 6 and 9, and the total must be a multiple of 10. For 111000025 the sum is 3 x (1+0+0) + 7 x (1+0+2) + (1+0+5) = 30. That checksum catches any single-digit error and most swaps of neighbors, but lets through a swap of two digits that differ by 5 (0 and 5, 2 and 7). The tool checks all of this in your browser, shows the arithmetic digit by digit and generates test numbers in bulk. It does not look up the bank that owns a number: the Fed's official directory, the E-Payments Routing Directory, has terms of use that prohibit commercial use of its data, so there is no bank name search here.
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<iframe
src="https://jkit.tools/embed/en-US/aba-routing-number-validator"
width="100%"
height="600"
style="border:0"
loading="lazy"
title="ABA Routing Number Validator and Generator"
></iframe>These references help contextualize formulas, standards, APIs and limitations used on this page. They do not replace professional validation when a result has legal, financial, medical or operational impact.
Multiply the 9 digits by the weights 3, 7, 1, 3, 7, 1, 3, 7, 1 and add them up: the number is valid when the total is a multiple of 10. To find the ninth digit, add only the first 8 products and take 10 minus the remainder after dividing by 10 (0 if the remainder is 0). In 111000025 the first 8 products add up to 3+7+1+0+0+0+0+14 = 25, 5 short of 30, so the ninth digit is 5.
1100-0000-0
| Digit | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
|---|---|---|---|---|---|---|---|---|---|
| Weight | 3 | 7 | 1 | 3 | 7 | 1 | 3 | 7 | 1 |
| Product | 3 | 7 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
3 + 7 + 0 + 0 + 0 + 0 + 0 + 0 + 0 = 10 | 10 mod 10 = 0
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