The verdict in three sentences
For an SME where 70-80 % of processes are standard (procurement, sales, accounting, stock), Odoo is almost always the right call in 2026. Custom becomes profitable only once business specificity exceeds 30-40 % and that specificity is a competitive edge. The real trade-off is not the entry price but the 5-year TCO and vendor dependency.
Odoo vs custom: the 5-year TCO
A 25-user London SME, 2026 order of magnitude, ex-VAT:
| Item | Odoo (Enterprise) | Custom ERP |
|---|---|---|
| Licence | EUR 24.90/user/month = EUR 7,470/yr | EUR 0 |
| Initial integration | EUR 15,000-50,000 | EUR 60,000-150,000 |
| Customisation | EUR 400-800/day | included in build |
| Annual maintenance | included in licence | 15-20 % of build |
| Hosting | 0 (Odoo cloud) | EUR 3,000-9,000/yr |
| 5-yr TCO (25 users) | EUR 70,000-110,000 | EUR 110,000-220,000 |
On this standard profile Odoo stays 30-50 % cheaper over five years. The maths flips as soon as Odoo modules require heavy customisation.
The business-specificity threshold
The further your processes drift from standard, the higher Odoo's hidden cost: each atypical business rule is paid for in custom development, then re-tested at every major upgrade.
| Share of specific processes | 2026 recommendation | Reason |
|---|---|---|
| 0-20 % | Standard Odoo | Config is enough |
| 20-30 % | Odoo + custom modules | Manageable customisation |
| 30-40 % | Grey zone, TCO arbitrage | Custom-Odoo cost near bespoke |
| 40-60 % | Custom recommended | Business fit decisive |
| > 60 % | Clearly custom | Odoo becomes a brake |
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Mini case study
Claire, CFO of a 30-person industrial SME in London, is torn. Odoo quote: EUR 35,000 integration + EUR 8,900/yr licences (30 users). But 45 % of her processes (batch management, specific quality control, material traceability) require heavy Odoo development, quoted at an extra EUR 40,000. Odoo 5-yr TCO: 35,000 + 40,000 + (8,900 x 5) = EUR 119,500. The Kolonell custom quote comes to EUR 95,000 + EUR 17,000/yr maintenance and hosting = 95,000 + 85,000 = EUR 180,000... but with no per-seat licence: at 60 users in three years Odoo would jump to EUR 17,800/yr in licences, flipping the maths. Verdict: custom wins once headcount grows sharply.
FAQ
Is free Odoo Community enough? For a micro-business yes, but Community loses the advanced functions (full accounting, studio, planning). Most SMEs move to Enterprise at EUR 24.90/user/month, which changes the TCO.
How much does an Odoo customisation cost? Budget EUR 400-800/day of integrator time in 2026, plus a recurring cost: every custom module must be re-tested at each major version upgrade (roughly one per year).
Does custom lock me into my vendor? Not if the code is your property and documented. Require source-code delivery, technical documentation and a reversibility clause in the quote.
How long for a custom ERP? Budget 4-8 months for a core-business scope in 2026, versus 6-12 weeks for a standard Odoo rollout. Time-to-market is part of the trade-off.
Can I mix both? Yes: keep Odoo for standard accounting/HR and build custom only the differentiating module, connected by API. That is often the best cost/value ratio.
Let's scope your project. Give us your headcount, your share of specific processes and an indicative budget, and we will price Odoo vs custom with a compared 5-year TCO. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
