In short: A B2B marketing agency is rarely as expensive as the monthly invoice suggests, and an in-house marketer is rarely as cheap as the salary suggests. a fair comparison in terms of cost requires a closer look.
A marketing manager earning a €70,000 annual gross package typically costs a Belgian company €115,000 to €135,000 per year once social contributions, overhead, tools, and hiring costs are included. For that money you get one person with one core skill set. An agency retainer of €7,500 per month (€90,000 per year) buys access to a strategist, SEO specialist, copywriter, designer, and paid media expert. The right choice depends on what you need, not on which number looks smaller.
All figures below are indicative estimates for Belgium. Check them against your own payroll and vendor quotes.
An agency that quotes €7,500 a month is quickly called expensive. A CFO or managing director often reacts like this:
“That’s €90,000 a year. For that money we can hire our own marketer!”
True. Maybe. But let’s look at the full picture first.
Take an experienced B2B marketing manager with a gross annual package of around €70,000, including the 13th month and holiday pay (again, this is a Belgian example). Then add:
Then there are the costs that don’t appear on any payslip. Salary continues during sickness and notice periods. Replacing someone costs time and money. A termination can carry a serious financial and legal price tag.
| Cost item (indicative, per year) | Amount |
|---|---|
| Gross salary incl. 13th month and holiday pay | €70,000 |
| Employer social contributions (~25%) | €17,500 |
| Extralegal benefits (meal vouchers, insurance) | €4,000 |
| Company car or mobility budget | €0 – €10,000 |
| Equipment, software seats, workplace | €6,000 |
| Training and conferences | €2,500 |
| Payroll and HR administration | €1,500 |
| Recruitment and onboarding (spread over ~3 years) | €6,000 |
| Martech stack (CRM, automation, SEO tools) | €5,000 – €10,000 |
| Total | €115,000 – €135,000 |
That is easily €115,000 to €135,000 per year, and sometimes more, for one person.
A B2B agency typically works with a retainer or a fixed number of days. An example:
A realistic all-in figure for the agency route in this example is €100,000 to €115,000 per year.
A full-time employee has roughly 260 weekdays per year. After statutory holidays, public holidays, sickness, and training, about 200 to 220 productive days remain.
On paper, the agency is more expensive per day. This is where most comparisons stop. But they should not.
Those 210 in-house days come from one person. That person might be excellent at demand generation, but how good are they at technical SEO, copywriting, design, marketing automation, and paid media analysis at the same time? Nobody handles all of these different marketing jobs perfectly.
The 120 agency days are spread across specialists. You pay for a senior strategist for a few hours, a copywriter for a few days, and a paid media specialist for a few days. You only pay for the expertise you use. To match that range in-house, you need a team:
| Scenario | Annual cost (indicative) | What you get |
|---|---|---|
| 1 in-house marketing manager | €115,000 – €135,000 | One generalist, ~205 productive days |
| In-house team of 3 (manager, content/SEO specialist, demand gen/marketing ops) | €300,000 – €350,000 | Broader coverage, still limited by individual skill sets |
| Agency retainer, 10 days per month | €90,000 + internal steering | Multi-disciplinary access, ~120 days |
| Full-service agency retainer, ~20 days per month | €180,000 – €250,000 | Strategy, content, SEO, paid, design, automation |
Now the difference between agency and in-house looks very different.
An employee is a fixed cost. You pay them in a strong quarter and in a quiet one, during a product launch and during a freeze. That is not a flaw, because it buys you continuity and commitment. But your cost per delivered result rises whenever your demand for marketing work dips.
An agency is largely a variable cost. You can scale up before a launch and scale down afterwards. The flip side is that you rent knowledge instead of owning it. When the contract ends, a good part of the know-how leaves with the agency.
Hiring a marketing manager takes three to four months to recruit, plus a notice period for the candidate, plus two to three months of ramp-up. It can easily be six to nine months before you see full impact.
A good agency can start within weeks. If you are launching a product, entering a new market, or rebuilding your pipeline, that time difference has a price. Every month without pipeline growth is also a cost, even if it never appears in a spreadsheet.
To be absolutely clear: we’re not saying you should always hire an agency. In a number of cases, hiring a marketing employee is better:
Many B2B companies choose a hybrid model: an in-house marketing lead who owns strategy, brand, and sales alignment, supported by an agency or freelancers for specialized execution such as SEO, paid campaigns, design, or marketing automation. The in-house person keeps the knowledge. The partner provides the outside view, scale and specialization.
A marketer who costs €125,000 and generates €600,000 in pipeline is a better investment than an agency at €80,000 that generates €150,000. The reverse is just as true. An agency that costs €100,000 and builds a repeatable lead engine is better value than a mediocre in-house hire who costs the same and delivers very little. We keep on saying that marketing is an investment into growth, and it should yield an ROI. Sadly many company leaders still treat marketing as a cost instead.
Before comparing prices, ask these questions:
Comparing an agency invoice with a salary is comparing apples with pears. A salary shows a fraction of the true employment cost, and an agency rate hides the breadth of expertise behind it. To make a fair comparison for your yourself and truly make the best possible decision, calculate both on the same basis: total cost, capacity, capability, speed, risk, and expected results.
In the end, you are not paying for a job title or a contract type. You are paying for the growth that marketing creates. This goes beyond the invoice or a payslip.
Per productive day, an agency usually has a higher rate. Per euro of delivered capability, it is often comparable or cheaper, because you access several specialists for the price of one fully loaded employee. Check the article for a concrete example, and when calculating this for yourself, get the actual numbers from your accounting and/or HR team.
For B2B companies in Belgium, retainers typically run from about €4,000 to €15,000 per month, depending on scope, seniority, and the number of disciplines. Media budgets are normally separate.
Expect roughly 1.6 to 1.9 times the gross annual salary once employer contributions, benefits, equipment, training, software, and recruitment are included.
When marketing is a continuous core function, when deep internal knowledge matters, and when the workload justifies a full-time role in a specific discipline.
Yes. This hybrid model is common: an internal lead owns strategy and alignment, while an agency delivers specialist execution.
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