Check structure, routing numbers, hashes, totals, trace numbers and control records. Free, no signup, and your file is processed locally in your browser.
Primary topic: ACH file validator
The ACH file validator checks whether an ACH file is structurally consistent and highlights issues that may prevent processing. Use this ACH file validator as a practical first step, then review its results carefully. a clean validation result does not guarantee bank acceptance because each ODFI can impose additional requirements.
A reliable ACH file validator workflow starts by confirming the business purpose before changing or exporting any data. This page is designed for checks whether an ACH file is structurally consistent and highlights issues that may prevent processing. It performs the supported work locally, so the source does not need to be sent to a conversion service. Use the ACH file validator with an approved source and a clearly defined expected result.
Start with a NACHA-formatted text file that you plan to inspect, repair or submit to a financial institution. Work from a copy, preserve leading zeros and remove unrelated report headings or totals that could be mistaken for transaction data.
Use the on-page controls, then compare the displayed batch count, entry count, total debits and total credits with the source expectation. Investigate warnings instead of assuming that a downloadable result is correct.
The expected result is diagnostics for record length, hierarchy, routing checksums, counts, hashes, totals, trace numbers, controls and padding. Before transmission or downstream import, review every error and warning, especially control mismatches, invalid routing numbers, unsupported SEC usage and malformed records, save the source separately and follow your organization’s approval process.
Confirm that the selected input really contains a NACHA-formatted text file that you plan to inspect, repair or submit to a financial institution. A renamed extension does not convert a spreadsheet, PDF or binary export into a valid ACH-related source.
Compare entries one batch at a time. Missing rows, duplicated rows, amount scaling, debit-versus-credit selection and malformed addenda can all change counts or monetary totals.
Format validation does not verify enrollment or bank policy. a clean validation result does not guarantee bank acceptance because each ODFI can impose additional requirements. Ask the ODFI for the rejection code and compare it with the company profile, identifiers and processing date.
It checks whether an ACH file is structurally consistent and highlights issues that may prevent processing. The ACH file validator processes the data locally in your browser and does not require an account.
It needs a NACHA-formatted text file that you plan to inspect, repair or submit to a financial institution. Files remain on your device during processing.
You will get diagnostics for record length, hierarchy, routing checksums, counts, hashes, totals, trace numbers, controls and padding. Review the result before using it in an operational workflow.
Check every error and warning, especially control mismatches, invalid routing numbers, unsupported SEC usage and malformed records. Also remember that a clean validation result does not guarantee bank acceptance because each ODFI can impose additional requirements.
It can report many record-level problems when the file remains parseable. Severely truncated, binary or incorrectly encoded input may need to be exported again before reliable analysis is possible.
An error identifies a structural or arithmetic problem likely to require correction. A warning calls attention to unusual or bank-dependent data that needs human review but may still be accepted.
No. Structural checks cannot confirm receiver authorization, account ownership, available funds, processing deadlines or the terms of your agreement with the financial institution.
Retain the source file according to your security policy and document the review outcome. Focus on every error and warning, especially control mismatches, invalid routing numbers, unsupported SEC usage and malformed records, along with any operational decisions made from the report.
Technical explanations are checked against these primary sources. Bank-specific requirements can be narrower than general format guidance.
Sources reviewed August 20, 2026. Nacha owns and maintains the linked materials.
ACH files use the NACHA fixed-width format: every record is 94 characters, files contain one or more batches, and control records reconcile entry counts, routing-number hashes, debits and credits. Always confirm bank-specific settings with your financial institution before uploading a production file.