Odoo vs Custom Build for a 40-Person Company in Amsterdam: 5-Year Cost

The verdict in three sentences

For a 40-person company, Odoo Enterprise and a custom application reach a similar 5-year cumulative cost, as a 2026 order of magnitude 170,000 to 190,000 EUR in a median scenario with French rates, and roughly 20 to 30% more at Amsterdam rates. The difference lies in the share of needs covered natively: above 75%, Odoo wins; below 60%, customizations cost more than a custom build. The classic trap is heavily customizing Odoo, then paying full price for every version upgrade.

The cost items in 2026

The CFO of a mid-sized company (aerospace subcontracting, engineering office, metal fabrication) handles complex multi-level quotes and cascading subcontracting. A standard ERP covers these processes poorly. Here are the real cost items.

An often forgotten point: as soon as you develop custom modules, the Custom plan at 37.40 EUR becomes mandatory. For 40 users, that is 17,952 EUR a year of licenses, close to 90,000 EUR over 5 years.

The 5-year cumulative calculation

Median scenario for 40 users at French rates: Odoo integration at 40,000 EUR with 6 custom modules, or a custom application at 100,000 EUR covering quotes, subcontracting, production and invoicing, connected to existing accounting software.

At near-equal cost, the question becomes functional. Measure native coverage per process before choosing.

The risks of each option

With Odoo, the main risk is customization debt: every custom module must be rewritten or adapted at yearly version upgrades, costing 5,000 to 20,000 EUR per migration and leaving some companies stuck on a version 3 years old. With a custom build, the risks are vendor dependency and a longer time to go-live. Require code ownership, technical documentation and automated tests covering at least 60% of business logic. A hybrid path exists: Odoo for accounting, purchasing and inventory, plus a custom application for quotes and subcontracting, linked by API (interface budget 8,000 to 15,000 EUR).

Mini case study

Sanne, CFO of a 40-person engineering subcontractor in Amsterdam, is torn. Each quote takes a sales engineer 3.5 hours on average, for 600 quotes a year, or 2,100 hours. A custom quoting application cuts that to 1.2 hours: 1,380 hours saved a year, 82,800 EUR at a loaded cost of 60 EUR an hour. With customized Odoo, the estimated gain is 1.8 hours per quote, 1,020 hours and 61,200 EUR. Over 5 years, the gain gap reaches 108,000 EUR in favor of custom for a total extra cost of 3,740 EUR at French rates. Sanne picks the hybrid route: Odoo Standard for accounting (12 users, 3,586 EUR a year) and a custom quoting module at 65,000 EUR with a nearshore team.

FAQ

How much does Odoo cost for 40 users in 2026?

Between 11,952 EUR a year (Standard at 24.90 EUR) and 17,952 EUR a year (Custom at 37.40 EUR), excluding 20,000 to 60,000 EUR of integration. The Custom plan is required as soon as there are custom modules.

What does a custom business application cost for a mid-sized company?

As a 2026 order of magnitude, 60,000 to 140,000 EUR depending on the processes covered, plus 12 to 18% a year for maintenance. Amsterdam agencies typically quote 20 to 30% higher.

Is an Odoo version migration expensive?

Without custom modules, it is almost free. With 5 to 10 custom modules, expect 5,000 to 20,000 EUR per migration and 4 to 8 weeks of testing.

Can we start with Odoo and move to custom later?

Yes, if you limit customizations. Data can be exported, but a switch costs 5,000 to 15,000 EUR of migration.

How long does a custom ERP take?

Count 6 to 10 months for a 40-person company, with go-live in batches from month 4.

Let's scope your project. We assess Odoo's native coverage of your processes and price the custom or hybrid option (budget, timeline, 5-year cost). Detailed quote within 48 h. WhatsApp +221 77 596 93 33.