IIF to CSV Converter

IIF (Intuit Interchange Format) is tab-delimited text, which makes it look like a spreadsheet that took a wrong turn. It is not one. An IIF file is a stack of small tables sharing a single document: each section opens with a header line beginning with an exclamation mark — !ACCNT, !CUST, !TRNS — that names the columns for the rows underneath it, and the rows themselves are tagged with the same keyword minus the mark. One file can therefore hold a chart of accounts, a vendor list, and a batch of transactions, all with different column meanings, stacked one after another.

Transactions add a second layer on top of that. QuickBooks is a double-entry system, so a single transaction occupies at least three lines: a TRNS line for the transaction as a whole and the account the money moved through, one or more SPL lines for the offsetting side, and an ENDTRNS line to close the group. The two sides carry opposite signs and must net to zero. A $340 vendor bill posted to two expense accounts is one TRNS line and two SPL lines, and reading only one of those lines out of context tells you something misleading.

This converter takes the TRNS lines and nothing else. It reads the !TRNS header to learn what the columns in this particular file are called, then writes one CSV row per transaction using those names — so the output carries the transaction type, date, account, name, class, total amount, document number, and memo, in whatever order the source file declared them. The result is the cash-side ledger view: every transaction once, at its full value, on a single row that Excel can sort, filter, and pivot without any further reshaping.

No TRNS rows were found. The file is almost certainly a list export rather than a transaction export. QuickBooks Desktop's own IIF export produces chart-of-accounts, customer, vendor, and item files, none of which contain a single TRNS line. Open it in a text editor: if the header lines read !ACCNT or !CUST and there is no !TRNS anywhere, there are no transactions in it to extract.

The amounts look like they are only half the transaction. They are the cash side of it. A TRNS line for a check shows the amount leaving the bank account as a negative, while the expense categories it was split across live on the SPL lines that were skipped. Sum the AMOUNT column and you get net cash movement, not total expenses by category — those are different questions and the CSV only answers the first.

Some rows are shorter than the header, leaving trailing columns empty. IIF rows are allowed to stop early when their remaining fields are blank, so a transaction with no class and no memo may simply end after AMOUNT. The CSV keeps the row as-is rather than padding it, which occasionally leaves ragged right-hand columns. Spreadsheets handle this without complaint.

A memo field broke the row into extra columns. IIF has no escaping mechanism — a literal tab inside a memo is indistinguishable from a field separator, so anything pasted into QuickBooks from another application can carry an invisible tab that splits the row. If one row has more columns than its neighbours, find it in the original file and remove the stray tab before converting.