--- title: "NACHA Navigator | Free NACHA File Viewer & ACH File Validation Tool" description: "Free NACHA file viewer and ACH file validation tool. Upload, parse, and analyze ACH files field-by-field, generate reversal files, and troubleshoot NACHA format errors. 100% in-browser — your file never leaves your device." canonical: https://nacha-navigator.com/ updated: 2026-10-30 --- # Read any NACHA file, field by field. Free NACHA file viewer & ACH validator Drop in an ACH file to see every 94-character record decoded field by field, in the right layout for each SEC code, including IAT, returns and NOCs. It checks totals, entry hashes, routing check digits, dates and codes against the NACHA format, and builds reversal files. Parsing happens entirely in your browser. - Field-level decoding - Control totals & check digits - Reversal files ## 100% in-browser. Your ACH file never leaves this device. ### Parsed on your device JavaScript on this page reads the file. Nothing is uploaded, stored or transmitted. ### No account, no cost Viewing, validating and building reversals are free. No sign-up, ever. ### Open about usage Our [public analytics](https://nacha-navigator.com/analytics) show exactly what we count — never what your files contain. **0 bytes** of your file are uploaded; the only requests are anonymous counters (a page view, a file opened). See for yourself in your browser’s developer tools (Network tab). Anatomy of a record ## Ninety-four characters, fully accounted for. Every line of a NACHA file is a fixed-width record. Navigator names each field, colors it by what it holds and measures exactly where it sits — so you can see at a glance where the routing number ends and the amount begins. **Line 03** Entry detail · PPD checking credit, from the sample file ### What each field holds **1 Record Type Code**: Identifies the type of record in the file. **2–3 Transaction Code**: Identifies the type of account and whether the entry is a credit, a debit, a prenote, a zero-dollar entry or a return/NOC. **4–11 Receiving DFI Identification**: First 8 digits of the routing number of the Receiver's financial institution (the RDFI). **12 Check Digit**: The ninth digit of the RDFI routing number, computed from the first eight. **13–29 DFI Account Number**: The Receiver's account number at the RDFI. **30–39 Amount**: The amount of the entry, in cents. **40–54 Individual Identification Number**: Number the Originator uses to identify the Receiver, such as an employee ID, customer or loan number. **55–76 Individual Name**: Name of the Receiver. **77–78 Discretionary Data**: For the ODFI or Originator to use as they agree; it has no meaning to the ACH Network. **79 Addenda Record Indicator**: Shows whether one or more Addenda Records follow this entry. **80–94 Trace Number**: Uniquely identifies the entry within its batch and lets it be traced through the ACH Network. Every record type, field by field: [the NACHA file format reference](https://nacha-navigator.com/nacha-file-format) What it does ## Catch it here, before your bank does. The same checks your bank runs before it accepts a file — record lengths, control totals, hashes and check digits — explained in plain language, line by line. No. 01 ### Decode Every record type — File Header (1), Batch Header (5), Entry Detail (6), Addenda (7), Batch Control (8) and File Control (9) — split into named, color-coded fields, with the right layout for PPD, CCD, CTX, WEB, TEL, IAT, returns and NOCs. No. 02 ### Validate Record length, control totals, entry hash, routing check digits, effective dates, SEC and transaction codes, and blocking-factor padding. Each problem is pinned to its line and column, with the expected value when there is a single right one. No. 03 ### Reverse Pick the entries to undo — one, a whole batch or the entire file — and download a reversal file: transaction codes flipped, control totals recalculated and the REVERSAL company entry description set. No. 04 ### Audit Reconcile debit and credit totals, entry and addenda counts and entry hashes against your payment register before you send, then export the entries to CSV or JSON. Related tools ## More free tools for payment files. The same private, in-browser approach for the other formats that land on an operations desk. X9.37 · Image cash letter New ### X9 Viewer Open X9.37 check image files in your browser. See every item’s front and back images, its MICR line and the record behind it — inspected the same field-by-field way, with bundle and cash letter totals checked. Opens `.x9` `.x937` `.icl` files [Open X9 Viewer](https://nacha-navigator.com/x9-viewer) BAI2 · Balance reporting ### BAI2 Viewer Turn BAI2 bank reports into readable account summaries and transaction detail, with every type code explained. [Open BAI2 Viewer](https://nacha-navigator.com/bai2-viewer) Build files · Builder and REST API ### NACHA Generator Build a valid NACHA file in the visual builder — or send JSON to the free REST API. Control totals, entry hash and block padding are done for you, and the result opens right here in the viewer. [Open the builder](https://nacha-navigator.com/nacha-generator) [Read the API docs](https://nacha-navigator.com/nacha-generator/api) ACH · Reversals ### ACH Reversal Reverse a whole NACHA file or just the entries you choose: transaction codes flipped, REVERSAL as the company entry description, the control totals recalculated and the five-banking-day window checked. [Reverse an ACH file](https://nacha-navigator.com/ach-reversal) Questions ## Before you open a file. Short answers to what people ask most. The full answers, with real-world use cases for payroll, banking, treasury and compliance teams, are on the [use cases page](https://nacha-navigator.com/use-cases). **Why was my NACHA file rejected by my bank?** Common rejection causes include incorrect record lengths (lines must be exactly 94 characters), unbalanced batch or file control totals, invalid routing number check digits, bad effective entry dates, missing blocking-factor padding (files must contain a multiple of 10 records), and malformed Standard Entry Class (SEC) codes. **How do ACH reversals work?** Under Nacha rules, an originator may reverse an erroneous entry (duplicate, wrong amount, wrong account, or wrong date) by submitting a reversing entry within five banking days of the settlement date of the original entry. **Is my ACH file data secure when I use NACHA Navigator?** Yes. NACHA Navigator parses your file entirely in your browser using client-side JavaScript. **What is a NACHA file?** A NACHA file is a fixed-width text file format defined by Nacha (the National Automated Clearing House Association) for submitting ACH payments in the United States. [Read every answer and the use cases](https://nacha-navigator.com/use-cases) ## Limits - It reads and checks files and builds reversals. It doesn’t send anything to your bank or the ACH Network: you submit files through your bank’s own channel. - Routing numbers are checked by their check digit only, so it can’t tell whether a bank or an account exists, is open or belongs to the receiver. [PayOps Kit](https://payopskit.com/), a sister site, has routing number tools. - It doesn’t know your bank’s (ODFI’s) own requirements, such as cutoff times, file names or a balanced file with offset entries. - It doesn’t edit files. Fix the system that made the file, or build a new one in the [NACHA Generator](https://nacha-navigator.com/nacha-generator). - Its checks are informational, not a compliance review. The Nacha Operating Rules are the authority, and NACHA Navigator is not affiliated with or endorsed by Nacha. ## Reference - [NACHA file format](https://nacha-navigator.com/nacha-file-format) Every record type and field, position by position. - [NACHA file errors](https://nacha-navigator.com/nacha-file-errors) What each check means and how to fix it. - [ACH transaction codes](https://nacha-navigator.com/ach-transaction-codes) What each two-digit transaction code means. - [ACH Reversal](https://nacha-navigator.com/ach-reversal) Reverse chosen entries or a whole ACH file. - [Sample files](https://nacha-navigator.com/sample-files) Example NACHA, BAI2 and X9 files to download and open. Last updated October 30, 2026 ## Need More Than File Analysis? Looking for enterprise-grade NACHA file generation, batch processing, or automated ACH workflows? We’re developing advanced tools for financial institutions and treasury departments. [Discuss Enterprise Solutions](mailto:davidkaylor95+nachanav@gmail.com?subject=Interest%20in%20NACHA%20File%20Generation%20Tools&body=Hi%2C%20I'm%20interested%20in%20learning%20more%20about%20NACHA%20file%20generation%20and%20editing%20capabilities%20for%20our%20organization.)