VAT, FODEC, stamp duty: the Tunisian order of calculation, and why it cannot be fixed later

The order, before the rates

Most discussions of Tunisian tax are about rates. That is the easy part: they are published, they rarely change, and a spreadsheet can multiply. What gets lost is the order in which the charges stack, because it cannot be read off a finished invoice — it can only be read off the way that invoice was built.

Three rules, three different levels:

• FODEC applies to the line — 1 %, calculated on the line's pre-tax amount, before anything else.
• VAT applies to the widened base — on the pre-tax amount plus FODEC, not on the pre-tax amount alone.
• Stamp duty applies to the document — a fixed amount per fiscal document, not per line and not per customer.

A spreadsheet that applies VAT to the pre-tax amount alone produces a total that looks right. It is wrong by a fraction of a per cent, systematically, in the same direction, on every line of every invoice of the year.

Stamp duty is a document, not a line

Stamp duty goes wrong for a different reason: people treat it as a product line. It is not. It is a fixed amount attached to the document, and it therefore follows the document everywhere it goes.

A credit note is a fiscal document in its own right: it carries its own. So do your purchase documents. And it does not follow quantity: ten lines or one, it is the same document, so the same stamp. An Excel template that puts stamp duty in the line table is wrong at the first credit note.

What a line remembers, and why it matters years later

An invoice is not a total. It is the record of what was taxed, at what rate and under which rule — and that record is what an audit asks for, sometimes long afterwards.

When a document is written, VIA ERP freezes on each line the tax that applies to it: its name, its official legal code, its rate, the level it applies at and its calculation rank. That record does not move. Change a rate next year and this year's documents keep theirs.

That is what makes a conversion safe. A quote invoiced six months later is taxed at the rate it was issued under, not at today's rate. A delivery converted into an invoice, a purchase order become a purchase invoice: the line carries its tax with it instead of recalculating.

A sequence that does not skip

Continuous numbering on fiscal documents is not an organisational nicety. An unexplained gap in an invoice sequence is an audit finding, and you then have to account for a number that does not exist.

Each document type has its own series: pattern, first number, digit count and reset — never, monthly, quarterly or yearly. And a number assigned to a record that fails is not consumed: it is taken by the next document. A refusal, a validation that breaks or a rollback does not tear a hole in the sequence.

The customer's regime decides their tax

In Tunisia, two customers buying the same product do not necessarily carry the same tax. The real regime, the flat-rate regime and agricultural activities are not treated alike, and that should not depend on the memory of whoever is keying the document.

That is what a fiscal position is for: it is attached to the customer and it remaps the taxes on their documents. Three are set up by default on a Tunisian workspace. They are configuration data, not exceptions typed by hand on every document.

The dinar counts in millimes

The Tunisian dinar has three decimals. That is not a display detail: a calculation engine that rounds to two decimals manufactures a gap on every line, and that gap turns up in a bank reconciliation. The dinar is set as base currency with its three decimals, its separator and its symbol placement, on screen and on documents alike.

What is already there on day one

When a Tunisian workspace is created, VIA ERP installs the reference data: six active taxes — VAT at 19 %, 13 %, 7 % and 0 %, FODEC at 1 % and stamp duty — five tax groups, three fiscal positions, eight banks with their SWIFT code, five payment terms, the dinar in millimes and the numbering prefixes in common use.

You adapt what is already there instead of building it, and that is true before your first import.

What this article does not promise

Electronic filing, a prepared VAT return, withholding tax and its certificates are on the roadmap. They cannot be enabled on any plan today, and nothing here sells them.

VIA ERP keeps your documents in a state fit to be presented. It does not file anything on your behalf, and you keep your accountant. Tunisian e-invoicing follows its own calendar: the page devoted to it says where it stands, without dating it.