CSV to IIF Converter: Complete Feature Guide & Reference
📄 Open the CSV to IIF Converter to try every feature described in this guide.
Open CSV to IIF Converter →Contents
What Is the CSV to IIF Converter?
The FinancialDataTools.com CSV to IIF Converter is a free, browser-based tool that transforms standard Comma-Separated Values (CSV) files into QuickBooks Intuit Interchange Format (IIF). All processing runs entirely inside your browser tab — no file is ever transmitted to any server.
The converter is built for bookkeepers, accountants, and developers who need to bring external data into QuickBooks without manual data entry. If your source data is in a spreadsheet or CSV export, this tool converts it to an IIF file you can import directly into QuickBooks.
Try the CSV to IIF Converter — runs entirely in your browser and never uploads your files.
Open the Converter →About the CSV Input Format
Comma-Separated Values (CSV) is a universally supported format exported by banking platforms, payroll systems, accounting tools, and spreadsheet applications. Your CSV file should have a header row as the first line, with one column per field you want to appear in the IIF output.
The converter accepts CSV files (.csv), tab-separated files (.tsv), and plain-text files (.txt) that follow a delimited structure. The delimiter is detected automatically — comma or tab. No pre-processing is required before loading.
About the IIF Output Format
IIF (Intuit Interchange Format) is a tab-delimited plain-text format used by QuickBooks to import financial records. The converter produces a valid IIF file structured as follows: a header definition line beginning with ! and the record type (for example, !TRNS), followed by one data line per CSV row using the selected record type name. The file closes with !ENDTRNS and ENDTRNS markers.
Column headers from your CSV become the field names in the IIF header line. Any tab characters within field values are automatically replaced with spaces to preserve the tab-delimited structure.
Choosing the Right IIF Record Type
The record type selector in the toolbar determines which IIF record type is used for your data. The available options and their typical uses are:
- TRNS — General journal transactions and bank transactions (most common)
- SPL — Split lines associated with a TRNS transaction block
- ACCNT — Chart of accounts entries
- CUST — Customer list records
- VEND — Vendor list records
- EMP — Employee list records
- INVITEM — Inventory item list records
- CLASS — Class list records
- OTHER — Any other IIF record type not listed above
Select the record type that matches the data in your CSV. If you are importing bank transactions, choose TRNS. If you are importing a chart of accounts, choose ACCNT.
The Toolbar
The toolbar across the top provides all primary actions for the conversion workflow. Use Open to browse for your CSV file, or drag and drop the file onto the source panel. Select your IIF record type from the Record type dropdown before or after loading. Once a file is loaded, click Convert to IIF to generate the output. Click Export IIF to download the result. The Reset button clears all state for a new conversion.
Source (CSV) Panel
The left panel shows your loaded CSV data as a table preview. Column headers from your CSV are shown in the header row and will become the field names in the IIF output. For large files, the preview is capped at 500 rows — a notice is shown if your file exceeds this limit. The full dataset is always converted regardless of the preview cap.
Output (IIF) Panel
The right panel displays the converted IIF output as plain text. Before conversion it shows a placeholder. After clicking Convert to IIF, the panel renders the full IIF content including the header definition line and all data lines. The panel is scrollable for any file size.
Output File Naming
The downloaded IIF file is named to match your input file — only the extension is changed to .iif. A file named transactions.csv produces transactions.iif. This keeps your file set organised without requiring any renaming.
Privacy & Security
The CSV to IIF Converter is built privacy-first. Your file is parsed and converted entirely inside your browser tab using JavaScript — no file content is ever transmitted to any server. This makes the converter appropriate for sensitive financial data including payroll exports, bank transaction files, and accounting records destined for QuickBooks import.
Closing the browser tab clears all data from memory. No data is written to localStorage or any persistent browser storage.
Use Cases for QuickBooks Import
Converting CSV to IIF is a practical step whenever you need to bring external data into QuickBooks. Common scenarios include importing bank transactions downloaded from an online banking portal, migrating customer or vendor lists from a legacy system, loading a chart of accounts from a spreadsheet into a new QuickBooks company file, and bulk-importing payroll or invoice records prepared in Excel.