Every few months a business owner tells me they are thinking about hiring a developer, and every few months I walk them through the same arithmetic. Not to talk them out of it. Sometimes hiring is right. But the sticker price on a job advert is not the cost of an engineer, and once the real number is on the table, the comparison with fractional engineering usually surprises people.
What an in-house engineer actually costs
A senior engineer in Europe typically costs somewhere in the region of €6,000 to €9,000 a month once you count everything that sits on top of salary: employer taxes and social contributions, pension, equipment, software licences, recruitment fees amortised over tenure, and the slice of management time it takes to direct someone’s work. On an annual basis that is roughly €72,000 to €108,000 for one person.
And it buys you one discipline. A strong backend engineer is rarely also your DNS and server-hardening person, your data-pipeline person, and your workflow-automation person. The gaps between those specialities are precisely where business systems fail, and one hire does not close them.
The utilisation problem nobody prices in
Here is the quieter cost. Most established businesses outside the software industry do not have forty hours a week of genuine engineering work. They have bursts: a build, a migration, a bad week, a quarter of improvements. In between, a full-time engineer is either idle, inventing work, or drifting into projects that did not need to exist. You pay for one hundred percent of their time and consume a fraction of it, which means your effective hourly cost is far above what the salary suggests.
The fractional math
Fractional engineering flips that. My Operate retainers run from €1,200 a month for monitoring, maintenance, and incident response, to €2,500 with active development hours, to €5,000 for a fully embedded partnership. Even the top tier sits below the bottom of the in-house range, and every tier covers all four disciplines: infrastructure, web, data, and automation.
Builds work the same way: fixed prices from €3,500, agreed in writing before work starts, with an operating period included so nothing is handed over and abandoned. The full numbers are public on the pricing page, because a cost comparison you cannot check is not a comparison.
When hiring in-house genuinely wins
Honesty matters here. If you have forty-plus hours of engineering work every single week, hire. If engineering is your product, hire, and probably more than once. If you need someone physically present in your office daily, hire. Fractional is not a discount substitute for a team; it is the correct shape for businesses whose systems matter commercially but whose engineering workload is real, recurring, and part-time.
The comparison in one paragraph
An in-house senior costs €6,000 to €9,000 a month for one discipline and a utilisation rate you will never measure. A fractional engineer costs €1,200 to €5,000 a month for four disciplines, with the idle time priced out of the model because it is shared across a small number of clients. The trade you are making is exclusivity, and unless you can genuinely fill a full-time week, exclusivity is the most expensive thing you can buy.
If you want the model itself explained first, start with what fractional engineering is. If you want to see how the maths applies to your systems specifically, a free 45-minute diagnostic call is where every engagement here begins.