Splitting invoice costs across departments by percentage

Some suppliers' invoices never look in the ledger the way they looked on paper. A warehousing, logistics, insurance or facilities invoice is not a list of goods — it is a shared company cost that has to be allocated to departments or projects every month in agreed proportions. Warehouse 80%, Distribution 15%, Imports 5% — and the same again next month.

The supplier knows nothing about that agreement. They send an invoice with twenty-one lines; the accountant needs three. And those three lines have to add up to the invoice total exactly, to the cent.

When costs get split by percentage

This is not an edge case. It is normal practice anywhere one service is used by several parts of the business and the document itself gives you no way to divide it.

• •Warehousing and logistics used by more than one business line
• •Rent, utilities, security and cleaning across shared premises
• •Insurance and other annual premiums covering the whole company
• •Telecom and IT billed once for every department
• •Shared administration or advisory services

What these invoices have in common is that the proportion was settled long ago and barely changes. Only the amount changes.

Why splitting by hand costs more than the time it takes

Time is not the biggest loss here. The biggest loss is that the same calculation is redone every month, and every recalculation is a fresh chance to get it wrong. Multiply a total by 15% and round each line on its own, and you are often left with a stray cent. It is trivial in size, but the invoice no longer agrees with its own total — and most accounting systems either reject that document or accept it with an error somebody has to chase later.

The second problem is that the proportions live in one person's head, or in a spreadsheet only that person opens. While the same accountant handles that supplier, everything is fine. When they change roles or take leave, the split quietly disappears and the whole invoice lands on one department — an error nobody spots in the reports until year-end.

How it works in Ezura

The proportion is set once, on the supplier's rule. You choose the "split by percentage" action, pick which dimension is being allocated — Department, Project, Site — and list the rows: a value and a percentage. From then on, every invoice from that supplier arrives for review already allocated.

• •The percentages must total 100 — a rule that doesn't will not save
• •Every allocation line carries its own department, project or site
• •It doesn't matter how many lines the supplier printed; you get the ones you defined
• •VAT is split in the same proportion rather than dumped on one line
• •The rounding remainder goes to the last allocation, so the total reconciles to the cent

That last point matters most in practice. It is the reason the invoice does not need a manual fix before it goes to the accounting system: the line total and the VAT always agree with the invoice's own figures, not approximately but exactly.

The accountant still decides

The review screen shows that the lines were produced by a rule rather than by the supplier, so nobody has to wonder why there are three lines on screen and twenty-one in the PDF. On any single invoice the lines can still be edited by hand, and the proportion can be changed in the rule whenever the underlying agreement changes. The system proposes the split; a person approves it.

When a percentage split is the wrong tool

Not every multi-department invoice is a percentage case. If the document itself already tells you who each item belongs to — goods with site codes, services against named projects, fuel against registration plates — splitting by percentage would throw away information the supplier has already given you. Percentage allocation is for costs the document genuinely cannot divide.

The practical test is simple: if the proportion is recalculated every month from actual usage, it is not a fixed percentage and a rule will not help. If it was agreed in a contract and repeats, it will.

What you need to prepare

Less than people expect. Three things: the dimension you allocate by (departments, projects or sites) with its values already in place; the list of suppliers whose invoices are always split; and the percentages themselves. In practice this is one conversation with the accountant, not a project.

Nothing changes in your accounting system. It receives the same dimensions you use today — already allocated instead of keyed in by hand.

Frequently asked questions

Can different suppliers have different proportions? Yes — the rule sits on the supplier, so one can split 80/15/5, another 85/10/5, and the rest not at all.

What if one month's split is different? The accountant edits that invoice by hand; the rule is untouched and behaves as before next month.

Do you lose sight of what the supplier actually sold? No — the original document stays attached to the invoice and can be opened at any time, even when the ledger sees three lines.