How IIF files work
IIF uses record headers and transaction lines rather than a simple flat table. Account names, transaction types, and balanced split lines require careful mapping.
The right conversion depends on whether the next step is human review, spreadsheet analysis, archival, or import into financial software. A converter should preserve transaction meaning rather than simply changing an extension.
How to open IIF
First identify the application that created the file and keep an untouched copy. Text-oriented formats can be inspected with a text editor, while spreadsheets and PDF documents require compatible viewers. Financial import formats should preferably be opened or imported by software that understands their account and transaction structures.
How to convert IIF
Choose an output based on the destination. CSV or Excel works well for review and analysis; QBO, QFX, OFX, QIF, or IIF may be required for accounting and personal-finance imports; PDF is best for a fixed readable report. Validate dates, signs, balances and identifiers before relying on a converted file.
IIF compared with related formats
IIF and CSV serve different parts of the financial-data workflow; IIF and Excel serve different parts of the financial-data workflow. The format name alone does not guarantee compatibility, so verify the destination application's supported versions and account types.
Supported IIF converters
Convert from or into IIF
Use an outgoing converter when IIF is your source. Use an incoming converter when another file must become IIF. Keeping those intents separate prevents accidental reversal of the workflow.