What is a NACHA file?
A NACHA file is the fixed-width format banks and payroll/payment processors use to move money through the ACH network — direct deposit payroll, vendor payments, subscription billing, and more. It's named after NACHA, the organization that governs the ACH network's operating rules. Every line is exactly 94 characters with no delimiters at all — fields are identified purely by character position, which made sense for the mainframes the format was built for decades ago but makes it unreadable without a parser. For the full anatomy of the format, read What is a NACHA file? in the Learn section.
Who works with NACHA files?
Banks, payroll providers, and payment processors generate and consume NACHA files as the literal instructions for an ACH batch — this is the exact file format a bank's ACH origination system submits to the Federal Reserve or a private ACH operator. Treasury and finance teams working with a bank's direct file delivery, or auditing what a payroll run actually submitted, are the most common people who need to read one outside of core banking software.
NACHA record types, briefly
Every line starts with a one-digit record type code. Five of them matter:
- 1 — File header: Who created the file (immediate origin) and who it's for (immediate destination), plus the creation date and time.
- 5 — Batch header: Starts a batch: company name and ID, the Standard Entry Class (SEC) code like PPD or CCD, and the effective entry date.
- 6 — Entry detail: One transaction: a two-digit transaction code, the receiving bank's routing number and account, the amount, and the receiver's name.
- 7 — Addenda: Optional extra remittance/payment-related text attached to the entry detail record right before it.
- 8 / 9 — Trailers: Close the batch and file with control totals — entry counts, an entry hash, and total debit/credit dollar amounts — used to detect a corrupted or truncated file.
The viewer walks this whole structure for you: it validates the batch and file control totals, links addenda records to the entry they belong to, resolves every transaction code to plain English (22 → Checking Credit, 27 → Checking Debit), and flattens everything into one row per entry with the addenda text merged in.
How to view a NACHA file
- Drop your .ach file above (or paste its contents). Parsing happens on your device — the file is never uploaded.
- Check the summary: file date, originator, batches with their SEC codes, and entry count, plus any validation warnings the parser found.
- Preview the flattened entries — plain-English transaction types, amounts, receiver names, and addenda text.
- Export as CSV for Excel, XLSX, or JSON.
Troubleshooting NACHA files
What do the NACHA transaction codes (22, 27, 32...) mean?
The two-digit transaction code on every entry detail record tells you the account type and direction: 22 is a checking credit (deposit), 27 is a checking debit (payment/withdrawal), 32/37 are the savings equivalents, and codes ending in 3 or 8 (23, 28, 33, 38...) are zero-dollar prenotifications used to verify an account before real money moves. This viewer translates every code to plain English automatically.
What is a NACHA entry hash, and why doesn't it match?
The entry hash is a simple checksum: the sum of every entry's 8-digit receiving bank routing number, truncated to the last 10 digits. It exists so a receiving system can detect a corrupted or truncated file, not to validate dollar amounts. If this viewer flags a hash mismatch, it means the batch or file control record's declared hash doesn't match what the entries actually sum to — worth investigating before you trust the file, but not necessarily evidence of a payment error.
If you're chasing down a returned payment instead, the bank's response uses a different code system entirely — see NACHA return codes explained.
What's the difference between a NACHA file and an ACH file?
Nothing structural — "NACHA file" and "ACH file" refer to the same fixed-width format, named after NACHA (the National Automated Clearing House Association) that maintains the ACH network's operating rules. You'll see both .ach and .txt extensions in the wild for the identical format.
Is this NACHA viewer really free?
Yes — every file parses and previews free with no signup and no upload. Free exports include the first 100 entries; a one-time $19 license unlocks unlimited exports on every LegacyFile tool.