Finance

Automating purchase invoices: what works now, and what stays human work

Reading invoices is no longer the hard part. Exceptions are. What you can hand over, what you should keep, and how to tell whether it pays off.

Published 1 October 2026 · by Mitchel van Gerwen

Where the invoices get checked: at the desk, by a person.

In many growing businesses, finance is where most hours quietly disappear. Purchase invoices are a good example: each invoice on its own is a few minutes of work, but there are many, they arrive through different routes, and every deviation costs an email or a phone call. The good news is that reading an invoice is no longer the problem. The question is what you set up around it.

What actually happens with one purchase invoice

The invoice arrives, usually as a PDF in a shared mailbox, sometimes on paper or through a portal.
Someone opens it and copies over: supplier, invoice number, date, amounts and VAT.
The invoice is matched to a purchase order, project or cost centre.
Someone checks whether it is right: was this ordered, was it delivered, is the amount correct.
The invoice is booked and queued for payment.

What you can automate well today

Collecting from the mailbox, reading the data, and preparing it in your accounting package. Software reliably pulls supplier, number, date, amounts and VAT from almost any invoice, even when every supplier uses a different layout. Based on earlier bookings it can also propose the ledger account or cost centre, and lay an invoice next to the matching purchase order. What remains for the person is an overview of invoices that are already filled in.

What stays human work

The decision. Should this be paid? Is this an invoice from a supplier we know, for something we received? Does the amount match what was agreed? That check stays with someone who knows the business, and rightly so: an invoice paid in error costs more than all the time automation saves. The difference is that this person now only checks, instead of first retyping everything.

Reading is solved, exceptions are not

Where it stalls in practice are the cases that are slightly different: a credit note, three invoices in one PDF, an invoice that has to be split over two projects, a supplier quoting a different bank account than last time. A good setup recognises those cases and sets them aside for a person, instead of guessing. So with any solution, ask not only what happens when things go right, but above all what happens when they are slightly different.

Package or custom?

First see what your accounting package can already do. Most packages have a function that reads invoices in and proposes a booking, and for a business with one set of books and few integrations that is often enough. Custom pays off when invoices have to be matched to projects or orders from another system, when there are several companies or locations, or when you want checks of your own the package does not know. That trade-off is covered in more depth in custom, package or low-code.

How to tell whether it pays off

For one month, count three things: how many purchase invoices come in, how many minutes one invoice takes on average from arrival to booking, and how often something has to be corrected. Multiply the first two and you know what it costs today. Do the same count again a month after the rollout. Without that baseline, any judgement afterwards is a feeling, in either direction.

Frequently asked

How many invoices do you need before this pays off?

There is no fixed number. Multiply invoices per month by minutes per invoice, and weigh that against what the solution costs. With few invoices, the function in your accounting package is often enough already; then that is the honest advice.

Does this work with our accounting package?

Usually, yes. The common packages have an integration through which invoices and bookings can be delivered. We first look at what the package already does, and only build what is missing.

What if an amount is read wrongly?

That is why a check remains. A good setup also recalculates by itself: do the lines add up to the total, does the VAT match the rate. If it does not add up, the invoice is flagged instead of passed on.

Where do you start if you are not sure this is your biggest time sink?

With counting, not building. Our time-tracking worksheet (in Dutch) has you write down per task, for one week, where the time goes. Or request the free business scan, and we look along from the outside.