Validate ACH files with our free tool

Ian Berryman
Aug 15, 2023
2 min read

Updated: Aug 7

We know that ACH files can be confusing, especially when something goes wrong. The NACHA format isn't overly complicated but it is opaque to the untrained eye. To alleviate these problems, we built a free NACHA file validator to assist you as you troubleshoot. Whether you're an accountant reviewing a payroll file or a treasury manager troubleshooting customer files, this guide will walk you through identifying and fixing the issues in your NACHA files.

If you want to bypass the troubleshooting and start creating valid and compliant ACH files, use ACH Pro.

NACHA Validator Features

Supports all standard entry class codes except ADV and IAT
Validates ACH file components including type 05 addenda (IAT, return and NOC addenda not supported)
Identifies all errors in a file rather than returning one at a time
Processes ACH files with thousands of transactions in seconds (tested with files with 20,000+ lines and 15,000+ errors)
Calculates aggregate fields such as entry hashes and amount totals to simplify troubleshooting
Verifies routing number check digits to help identify typos
Runs in your browser without a server component so all data stays on your device

Validate an ACH File

To get started, drag a file into the validator or click to browse. Note that the validator only accepts .txt and .ach file types.

The validator will update with the contents of your file, as well as any errors.

Hovering over a field displays its name and clicking a field highlights any applicable errors for its line. In the example below, the batch number is invalid because it contains a letter.

If you see errors, we recommend you make a copy of your file and open it in a text editor like Notepad. Take note of the line number and field location when making changes. Errors for calculated fields like amount totals and hashes will include the expected amount. Be sure you change any related fields before changing calculated fields since the totals may change.

The header of the validator provides several useful fields such as amounts and line count, as well as the number of errors (if any). Keep in mind that the calculated fields are based on fields in the file that may have errors, so be sure to fix errors before relying on these fields.

When you're ready to validate your file again or want to validate a new file, refresh the page to reset the validator. If you've made all the necessary changes, the validator should present you with a success message.