Full-Time Engineer vs Backend Contractor — A Cost Breakdown for EU Startups

The number on the offer letter is not the cost

Your candidate accepted a €90,000 gross salary offer. You budget €90,000 per year. Then payroll runs and you discover that employer social contributions in Germany add another €18,000-20,000. Mandatory pension contributions, health insurance co-payment, unemployment insurance, nursing care insurance — these are not optional and not visible in the salary negotiation. The true cost of that hire is €108,000-110,000 before a laptop, desk, software licenses, or equity.

This is the most common hidden cost surprise in EU startup hiring, and it makes the full-time vs contractor comparison more nuanced than most CTOs initially expect.

True cost of a full-time engineer in major EU markets (2025 figures)

Employer costs vary significantly by country. For a senior backend engineer at €90,000 gross salary:

Germany: Employer social contributions run approximately 20-21% of gross salary. Total employer cost: ~€108,000-€109,000. Additional: 25 days statutory leave minimum (30 is market standard), 6 weeks of continued salary payment during illness (Entgeltfortzahlung), and the Kündigungsschutzgesetz (dismissal protection law) makes termination expensive and procedurally complex after six months.

Netherlands: Employer contributions include WAO/WIA (disability insurance), WW (unemployment), and ZVW (health) contributions totaling roughly 18-22% depending on salary. Total employer cost at €90K gross: approximately €105,000-€110,000. Dutch employment contracts also carry strong statutory protection; notice periods are legally defined based on tenure.

France: French employer social charges are among the highest in the EU — typically 40-45% of gross salary for cadres (senior roles). A €90,000 gross engineer costs approximately €126,000-€130,000 to employ. In return, employees receive comprehensive social coverage including robust public healthcare and pension entitlements.

Spain: Employer contributions run approximately 30-32% of gross. Total cost for €90K gross: ~€117,000-€119,000.

Poland: Lower gross salaries (a senior backend engineer at €40,000-€60,000 gross is competitive) with employer contributions around 20%. Total cost for €50K gross: approximately €60,000. This is why Poland appears frequently in nearshoring discussions — the actual employment cost is substantially lower while skill levels are high.

True cost of a contractor

A senior backend contractor in Western Europe (Germany, Netherlands, UK) typically rates €700-€1,100 per day for specialized backend work. For a 220-working-day year:

• 6 months engagement (130 days): €91,000-€143,000
• Full year engagement (220 days): €154,000-€242,000

The absence of employer social contributions, statutory leave accrual, equipment, health insurance co-payments, and dismissal liability is baked into the daily rate. The contractor absorbs these costs themselves.

For a 6-month engagement on a specific project, a contractor at €800/day costs €104,000 — comparable to a German full-time engineer but with no ongoing obligation, no dismissal risk, and no benefit administration.

For a 2-year engagement, the math inverts: a full-time engineer at €108,000/year fully-loaded costs €216,000 over two years; a contractor at €800/day for 440 days costs €352,000. The permanent hire is significantly cheaper over longer time horizons if you have steady work.

What the cost calculation does not capture

Ramp-up cost: A new full-time hire typically reaches full productivity in 3-6 months in a complex codebase. That is €27,000-€54,000 in fully-loaded cost before maximum output. An experienced contractor who has done similar work repeatedly often reaches meaningful productivity in 2-4 weeks.

Knowledge retention: When a contractor finishes and leaves, they take their context with them. You want to ensure documentation, architecture decisions, and institutional knowledge are captured before a contractor engagement ends. This is a real operational cost that is easy to ignore.

Legal risk in contractor classification: Germany's Scheinselbstständigkeit (false self-employment) rules and similar regulations in the Netherlands and France mean that contractors working exclusively for one client, on-site, following client-directed schedules, can be reclassified as employees retroactively. The tax and social contribution liability falls on the employer. Proper contractor agreements, limited engagement scope, and genuine independence are required — this is not theoretical risk, it is a common audit finding.

When each model is the clear choice

Full-time hire when:

• The role covers ongoing work for 18+ months
• Deep domain knowledge accumulation is part of the role's value
• The cost difference over time favors it (it does, beyond 12-18 months of comparable engagement)
• You are building team culture and continuity matters

Contractor when:

• Scope is defined and time-bounded (a migration, a new service, a specific integration)
• You need specific expertise not in the team's current skill set
• You cannot afford the notice period and dismissal procedure risk for a role that might not be needed in 12 months
• Speed to contribution matters and ramp-up cost is significant relative to the engagement length

Run the numbers for your specific country and engagement length before the conversation. The answer changes substantially depending on whether you are in Germany or Poland, and whether the engagement is 3 months or 3 years.