IIF Validator

Drop any .iif file to instantly check its structure. Validates QuickBooks Intuit Interchange Format files — checks record types, header/data line pairing, transaction block integrity (TRNS/SPL/ENDTRNS), required fields, encoding, and previews the first records. Nothing leaves your browser.

IIF File

📄

Drop a .iif file here, or browse Supports .iif files up to 50 MB

⛔ Wrong file type — only .iif files are supported. You dropped a file.

Validation Errors

Warnings

✓ Valid IIF

Record Types Found

Data Preview (first TRNS block)

How It Works

Drop your IIF fileDrag it onto the drop zone or click "browse" to select it from your device. Supports .iif files exported from QuickBooks.

Structure analysisThe validator parses every line, verifies header lines (! prefixed) pair with their data lines, checks transaction blocks open and close correctly, and validates required fields.

Review the reportGet a pass/fail result plus full stats: total lines, record types found, transaction count, split count, encoding info, and a preview of the first transaction block.

What Gets Validated

Header/data line pairing — every data line type (e.g. TRNS, ACCNT) must be preceded by a matching header line (e.g. !TRNS) that defines its columns.
Transaction block integrity — every TRNS line must be followed by at least one SPL line and closed by an ENDTRNS line. Unclosed or nested blocks are flagged.
Column count consistency — each data line's tab-delimited field count is compared against its section header definition. Mismatches are reported with line numbers.
Required fields — checks that TRNS records contain ACCNT, AMOUNT, and DATE columns, and that SPL records contain ACCNT and AMOUNT.
Amount format — verifies that values in AMOUNT fields are valid numbers. Non-numeric amounts are flagged.
Date format — checks DATE fields match QuickBooks' expected M/D/YY or M/D/YYYY format.
Encoding issues — detects a UTF-8 BOM and null bytes that indicate binary content or wrong encoding.
File statistics — reports total lines, record type summary, transaction count, split count, file size, and line ending style.
Data preview — renders the fields of the first TRNS block in a formatted table so you can visually confirm the parse is correct.

🔒 Privacy & Security

All validation is performed locally using the Web File API and the FileReader API. Your IIF data is never sent to a server. Suitable for sensitive financial records, customer lists, or any private QuickBooks data.

Related Guides & Tutorials

Guide

QuickBooks IIF File Format Explained

A complete breakdown of IIF structure — header lines, TRNS/SPL/ENDTRNS blocks, required fields, and why the format works the way it does.

Guide

Fixing QuickBooks IIF Import Errors

The most common reasons IIF files fail to import and how to diagnose and fix each one — from column mismatches to malformed transaction blocks.

Frequently Asked Questions

What is an IIF file?▼

IIF (Intuit Interchange Format) is a tab-delimited text format used by older versions of QuickBooks to import and export data — including transactions, accounts, customers, vendors, and items. Each section begins with a !-prefixed header line defining columns, followed by data lines using those columns.

Why does my IIF file fail to import into QuickBooks?▼

The most common causes are: a TRNS block missing its closing ENDTRNS line, a data line with more or fewer tab-delimited fields than its header definition, a missing required field (ACCNT, AMOUNT, or DATE on TRNS), or an invalid date format. Run the validator first — it flags the specific line and issue.

Is my financial data sent to a server when I validate?▼

No. All validation runs locally using the browser's FileReader API. Your IIF file is read into memory in your browser tab and never transmitted anywhere. This tool is safe to use with real production data, customer records, and sensitive financial files.

What QuickBooks versions use IIF files?▼

IIF import/export is supported in QuickBooks Desktop (Pro, Premier, Enterprise) going back to early versions. QuickBooks Online does not support IIF import — it uses QBO and QFX formats instead. If you are migrating data to QBO, IIF files must be imported into Desktop first or converted to another supported format.

What does the column count mismatch error mean?▼

Each data line must have exactly as many tab-delimited fields as the corresponding header line defines. If your !TRNS header has 10 columns but a TRNS data line has 9 or 11 fields, QuickBooks will reject the record. This often happens when fields containing commas or special characters are not properly handled during export.

What date format does QuickBooks IIF expect?▼

QuickBooks IIF expects dates in M/D/YY or M/D/YYYY format — for example 3/15/24 or 3/15/2024. ISO format (2024-03-15) and other formats will cause the record to be rejected. The validator flags any DATE field that does not match this pattern.