ACH File Converter

ABA Routing Number Validator

Validate a nine-digit ABA routing number checksum locally in your browser.

Enter all nine digits to run the ABA checksum test.

A valid checksum confirms the number's mathematical structure only; it does not prove the bank or account is active.

Use the routing result carefully

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What the checksum test confirms

The weighted checksum detects many typing and transcription errors in a nine-digit routing number. A passing result means the number is structurally plausible.

Prefix and format checks

The validator also checks numeric length and recognized routing prefix ranges before applying the checksum formula.

What cannot be verified from nine digits alone

  • Whether the financial institution is currently active.
  • Whether it accepts ACH entries.
  • Whether the receiver account exists.
  • Whether the routing and account combination is authorized.

Using a routing number in an ACH entry

ACH Entry Detail Records store the eight-digit routing prefix plus a check digit. Confirm the value with an authoritative bank or receiver source before production use.

Questions about ABA routing validation

What is an ABA routing number?

It is a nine-digit identifier used for a financial institution or processing endpoint in U.S. payment systems.

Does a valid checksum prove the bank exists?

No. The checksum only tests the number pattern; it is not a live directory lookup.

Can the validator confirm an account number?

No. Account ownership and status require a separate authorized verification process.

Which authoritative sources support this page?

Technical explanations are checked against these primary sources. Bank-specific requirements can be narrower than general format guidance.

  1. Nacha ACH File Details — Official record-field guidance, including Batch Header SEC codes and addenda capabilities.
  2. Nacha ACH File Overview — Official explanation of files, batches, entries, controls, and batch grouping.
  3. Nacha: How ACH Works — Official overview of ACH participants, consumer and corporate payments, and authorization responsibilities.
  4. Nacha Operating Rules Topics — Current rule changes and implementation topics published by Nacha.

Sources reviewed August 20, 2026. Nacha owns and maintains the linked materials.