Belgium - NL
Whether you're a freelancer, a small business owner or a representative of a large company, the quotation is often the first real step toward a collaboration. But what exactly is a quote, and why is it so much more than a simple list of prices?
A quotation is a formal document in which you explain to a potential client what you are offering, what it will cost and under what conditions. By doing so, you show not only what you will deliver, but also that you work professionally, have listened carefully to the client's wishes, and communicate clearly.
No, quotes are not required by law. Nevertheless, in many sectors - such as construction, consulting or creative services - it is customary to provide a quote in advance. By preparing a clear quotation in advance, you avoid discussions afterwards. Moreover, in this way it is clear to the (potential) client what goods and services will be delivered at what price.
Although an offer is not mandatory, in most situations it is mandatory to draw up an invoice once the service has been provided. That invoice must meet certain conditions under Belgian law, and can be sent either on paper or electronically.
Important: from January 1, 2026, structured electronic invoicing will become mandatory for all VAT-registered companies in Belgium. This means that from then on, invoices must be sent in a structured format (such as UBL via the Peppol network) so that they can be processed automatically by accounting software. This new legislation is part of the fight against VAT fraud and will further digitize administrative processes.
Whether an offer is binding depends on the type of offer you make. In law, offers are also called "offers. Specifically, there are the ordinary offer and the non-binding offer.
Ordinary (binding) quotation
With an ordinary offer, you are bound by your proposal. That means:
Tip: It is important to always attach conditions and a validity period to this. For example, "This quote is valid for 30 days from date of creation."
Free quote
A no-obligation offer gives you more flexibility. You may, as the seller, modify the terms until the customer explicitly agrees. Once the customer accepts the offer, the agreement becomes binding. Only by revoking your offer shortly after acceptance can it still be cancelled.
You send a quote, the client agrees, and you get to work enthusiastically. But during the execution of the job, there turn out to be extra costs - more hours, more expensive materials, or an unexpected change. And then the question arises, "Can you adjust the invoice? And if so, by how much?"
The answer depends on the type of agreement you made with your client.
Quote: a fixed price agreement
In most cases, a signed or accepted quote is considered a firm price agreement. Thus, the client may assume that the amount quoted is final.
Do you want to invoice more than stated in the quotation? Then this is only allowed in exceptional situations:
Without such an agreement, a higher invoice is not just legally valid. In many cases, a Belgian judge will rule in favor of the customer.
Target price: a little more slack
If, instead of a fixed quote, you gave a target price, you have a little more freedom. A target price is an estimate, not a fixed amount. You then state, for example, "Indicative quote, subject to change."
Still, there are rules here, too:
Billtobox makes it easy to create and send quotes. Once the quote is approved by the customer, you can easily convert it into an invoice. More info on how to create a quote in Billtobox can be found in our helpdesk article.
A good quotation is your first chance to make a strong impression. It provides clarity, prevents discussions and helps you come across as professional. And with tools like Billtobox , quotation management becomes simple and efficient.
The smartest way to receive, process and pay inbound invoices, generate and send outbound invoices, get paid and maintain a complete overview.
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