Custom software vs Odoo: the real cost in London 2026

The verdict in three sentences

Odoo wins when your processes fit the standard: fast rollout, lower entry cost, shared maintenance. Custom wins when your process IS your competitive edge: full business fit, zero per-user licences, vendor independence. The 2026 tipping point sits around 30 to 40 users or a business process that does not fit within 70 % of Odoo's standard modules.

Odoo vs custom: the 2026 cost structure

The two approaches cannot be compared on the initial quote alone. Odoo charges a setup (integrator) plus a recurring per-user subscription; custom charges a build plus a flat annual maintenance. 2026 order of magnitude on the London market:

Odoo's classic trap is heavy customisation: as soon as you leave the standard, every specific module is billed and must be re-tested on each annual version upgrade.

The 5-year TCO, the only honest comparison

Take a 30-user SME. Odoo: 35,000 EUR setup + 30 x 450 EUR x 5 years = 67,500 EUR licences + 20,000 EUR customisation = 122,500 EUR over 5 years. Custom: 80,000 EUR build + (14 % x 80,000) x 5 years maintenance = 56,000 EUR = 136,000 EUR over 5 years.

At 30 users Odoo stays cheaper; at 60+ users the recurring licences tip the balance toward custom, which becomes an asset you own rather than a subscription that rises with headcount.

Mini case study

Thomas, operations director of a 45-employee logistics SME in London, compares the two. His route and proof-of-delivery process is highly specific: Odoo would require 28,000 EUR of customisation on top of setup. Over 5 years Odoo costs him 35,000 + 28,000 + (45 x 450 x 5) = 164,250 EUR. Custom, built exactly on his process, comes to 95,000 EUR build + 66,500 EUR maintenance = 161,500 EUR, with no licence climb if he grows to 70 staff. He picks custom for business fit and independence.

FAQ

Is Odoo always cheaper upfront? Yes, almost always: the 2026 entry cost is 15,000 to 60,000 EUR versus 40,000 to 120,000 EUR for custom. The gap closes with user count and customisation volume.

When does custom become worthwhile? Beyond 30 to 40 users, or when more than 30 % of your processes fall outside Odoo's standard. Per-user licences (300-580 EUR/yr) then become the dominant cost.

What happens on Odoo version upgrades? Each annual version can break your custom modules; budget 3,000 to 10,000 EUR of re-testing and adaptation per major migration.

Can you self-host Odoo? Yes, Odoo Community is open source and self-hostable, but you lose vendor support and must internalise updates, roughly 10 to 25 person-days per year.

Does custom create agency dependence? Only if the code and documentation are not handed over. Demand source-code delivery, technical docs and a knowledge transfer: it is an asset you own.

Let's scope your project. Tell us your headcount, your 3 most specific processes and your target budget (40-120k EUR): within 48h we'll tell you whether Odoo or custom is more cost-effective for you. Detailed quote within 48h. WhatsApp +221 77 596 93 33.