CSV, XLSX, OFX, QBO, QIF, and MT940 formats explained
By Arron Child, reviewed by Arron Child. Updated 15 July 2026.
Bank data moves in half a dozen file formats, most of them invented decades apart for different software. Here is what each one actually is, what reads it in the UK, and why a careful CSV plus a typed XLSX covers most bookkeeping work.
The formats
CSV
Plain text, one row per transaction. Universally readable, trivially inspectable, and entirely convention-based: date format, column order, and amount signing are all up to the producer, which is why importers have mapping screens. Details on producing a good one.
XLSX (Excel)
A real spreadsheet with typed cells: dates that sort, amounts that sum with currency formatting. Better than CSV for human review; slightly worse as an interchange format because software importers mostly still want CSV.
OFX (Open Financial Exchange)
A structured XML-ish format from the late 1990s carrying transactions plus account metadata and, crucially, a unique ID per transaction (FITID) that lets software deduplicate across overlapping downloads. FreeAgent and many desktop packages read it. Verbose, rarely hand-fixable.
QFX and QBO
Vendor-flavoured OFX. QFX is Intuit's Quicken variant; QBO is the QuickBooks desktop variant. Functionally OFX with licensing fields; only relevant if your software insists.
QIF
Quicken's older plain-text format, no transaction IDs, ambiguous dates. Still accepted by FreeAgent and some tools, but there is rarely a reason to choose it today.
MT940
The SWIFT interbank end-of-day statement format, common in corporate banking and treasury systems, essentially never asked of a small UK practice. If a client's ERP wants MT940, the bank itself is usually the right source.
Which UK software wants what
| Software | First choice | Also accepts |
|---|---|---|
| Xero | CSV (signed amount) | OFX via bank feeds history |
| QuickBooks Online | CSV (3 or 4 column) | QBO, OFX |
| FreeAgent | CSV (3 column) | OFX, QIF |
| Sage Business Cloud | CSV | OFX in some plans |
| Excel / analysis work | XLSX | CSV |
Why ukbankconv exports only CSV and XLSX
Because they are the two formats whose failure modes we can make visible and verifiable: you can open both, read them, and check them against the statement. OFX-family exports are a plausible future addition, but only with the same verification guarantees, and never at the cost of getting CSV subtly wrong. The formats are few on purpose; the checking is the product.
Reviewed 15 July 2026.