What does in-house bookkeeping really cost?

The salary is just the starting point

An experienced accounts clerk in Brussels earns around €3,300 gross a month in 2026. With employer contributions, the cost to the employer exceeds €4,300.

On top of that come double holiday pay and the year-end bonus, which together add almost two extra months’ salary over the year.

The costs people forget

They appear on no payslip, but they are real:

• The workstation, software licences and ongoing training.
• Holiday weeks, during which documents pile up.
• Recruitment and the learning period every time someone leaves.
• The senior accountant’s time spent checking and correcting.

Bringing it down to a cost per document

A bookkeeper handles an average of 30 to 40 documents an hour on a well-organised file, far fewer on a messy one. Over a month of 150 productive hours, the full cost often comes to €1.50 to €3 per document.

By comparison, our rates start at €0.80 for a sales invoice and €1.10 for a purchase invoice, review included.

When to keep bookkeeping in-house

Outsourcing is not always the right answer. If your documents call for very detailed knowledge of the trade, or if your bookkeeper also covers reception and logistics, keeping them in-house can make sense. Most often, our clients keep one person in-house and hand the volume to us.