Routing number checker

Two things, independently. First, whether the nine digits are internally consistent: the last one is a checksum over the other eight, so a mistyped number usually fails on arithmetic alone. Second, whether the number appears in the Federal Reserve ACH directory extract behind this site — 18,198 routing numbers filed under 10,548 institution names.

• Fails the check digit — the number is wrong. Read it again from the source.
• Passes but no match — the digits are plausible and nothing here uses them. Unverified, not confirmed.
• Passes and matches — a real institution files it. Still not proof it is right for your account or payment type.

The ninth digit carries no information about the bank. It is a checksum over the first eight, weighted 3, 7 and 1 in a repeating cycle. All 18,198 numbers in this directory satisfy it.

1. 01Multiply digits 1, 4 and 7 by 3.
2. 02Multiply digits 2, 5 and 8 by 7.
3. 03Take digits 3, 6 and 9 as they stand.
4. 04Add the nine results — a valid number totals a multiple of ten.

On 021000021, which JPMorgan Chase files with the Fed: 3 × (0 + 0 + 0) is 0, 7 × (2 + 0 + 2) is 28, and 1 + 0 + 1 is 2 — total 30, so it passes.

Digits 1–4

Federal Reserve routing symbol; the first two name the District — 01 Boston, 12 San Francisco

First digit + 2

Denotes a thrift: 21 in the First District, 32 in the Twelfth

Digits 5–8

The institution’s own identifier

Digit 9

The check digit, computed from the eight before it

It is a typo trap, not proof a number exists. Because the weights 3, 7 and 1 share no factor with ten, altering any single digit always breaks the total — every one-character typo is caught.

• Swapping two neighbouring digits is caught too, unless they differ by exactly five: 27 typed as 72, or 49 as 94, sails through.
• Roughly one nine-digit number in ten passes by chance, because the ninth digit is whichever one makes the sum come out even.
• Only 18,198 are live in this directory. A checksum pass is weak evidence; a directory match is the strong one.

1. 01Reading it off a deposit slip. The IRS tells filers to ask their bank when the deposit-slip number differs from the one on their checks: slips can carry an internal number.
2. 02Trusting a “payable through” check. Regulation CC is explicit: where a check is payable by one bank but payable through another, the number printed on it is the payable-through bank’s.
3. 03Using the wire number for an ACH payment. The Fed publishes FedACH participants and Fedwire participants as separate directories; being in one says nothing about the other.
4. 04Assuming one number per bank. Here, 2,133 of 10,548 directory entries carry more than one, and Bank of America, N.A. files 148.
5. 05Reading the strip along the bottom of a check by position. The IRS warns on its own sample check that the routing and account numbers may sit in different places.

A checker validates a number; only the bank can confirm it is the right number for your account. The IRS names three situations where the instruction is to ask rather than infer:

• The routing number on your deposit slip differs from the one on your checks.
• The deposit is going to a savings account that does not let you write checks.
• Your checks say they are payable through a different financial institution.

Not every routing number belongs to a bank, either. The IRS accepts only numbers beginning 01 through 12 or 21 through 32 on a refund; 18,197 of the 18,198 here obey that. The exception, 655060042, is the Social Security Administration’s.

Routing numbers address the US payment system and nothing outside it. An overseas sender needs your bank’s SWIFT/BIC code and your account number — Chase gives senders CHASUS33 for an international wire and 021000021 for a domestic one.

When money starts in another currency, the routing number decides where it lands and the rate decides how much arrives. Conversions on Glide are quoted at the mid-market rate, with the cost charged as a visible fee rather than buried in the rate.