VAT difference on supplier orders in Dolibarr: Mode 1 or Mode 2?
You enter a supplier order in Dolibarr, and the VAT total lands a few cents away from the confirmation received from the supplier. Nothing is broken: it is a rounding question. Here is why, and how to align Dolibarr with your supplier's method.
Why this few-cents difference?
VAT can be computed in two ways, which sometimes give a slightly different result:
- Mode 1 — line-by-line rounding: each line's VAT is rounded, then summed.
- Mode 2 — rounding on the total: the bases are summed, then VAT is applied and rounded once, on the total.
On an order with many small lines, the two methods can diverge by 1 or 2 cents. If your supplier computes in Mode 2 and Dolibarr in Mode 1, your purchase order will not exactly "match" the confirmation.
The friction point in Dolibarr
On supplier invoices, Dolibarr already natively offers the Mode 1 / Mode 2 switch. But on supplier orders, that choice does not exist: you are stuck with the default method, unable to match the received confirmation.
The solution: add the choice on the order
The ideal is to have, on the supplier order card, the same Mode 1 / Mode 2 switch as on invoices — with a persistent choice, re-applied on every recomputation (line added, edited or removed). Your order then matches the supplier's to the cent, with no workaround or adjustment line.
The Qwimo module “Supplier order VAT mode”
Adds the Mode 1 / Mode 2 VAT rounding choice on supplier orders, exactly like on invoices. Persistent choice, no core modification. Dolibarr 16 → 23.
Discover the module →Frequently asked questions
Why does my VAT total differ from the supplier's?
Does Dolibarr handle this choice on supplier orders?
Does the Dolibarr core need modifying?
custom/ (extrafield + hook), without touching the core. Compatible with Dolibarr 16 → 23.Also read: syncing Falco / Horus payments and the Recupel eco-contribution on your invoices.