The verdict in three sentences
For 150 users, a SaaS billed at EUR 45 per user per month represents EUR 405,000 over 5 years, while a custom business platform at EUR 120,000 excluding VAT comes to about EUR 210,000 including maintenance and hosting. Once you include the 6 build months during which your current tool keeps running, break-even is around month 28. Custom only pays off if your processes are genuinely specific and you have an internal sponsor to steer the project.
Total cost of ownership, year by year
The calculation below compares cumulative cash out, excluding inflation. For custom, maintenance and hosting represent about EUR 18,000 per year (15% of the initial budget).
| Year | SaaS: annual cost | SaaS: cumulative | Custom: annual cost | Custom: cumulative |
|---|---|---|---|---|
| Year 1 | EUR 81,000 | EUR 81,000 | EUR 138,000 (120,000 + 18,000) | EUR 138,000 |
| Year 2 | EUR 81,000 | EUR 162,000 | EUR 18,000 | EUR 156,000 |
| Year 3 | EUR 81,000 | EUR 243,000 | EUR 18,000 | EUR 174,000 |
| Year 4 | EUR 81,000 | EUR 324,000 | EUR 18,000 | EUR 192,000 |
| Year 5 | EUR 81,000 | EUR 405,000 | EUR 18,000 | EUR 210,000 |
| 5-year gap | EUR 195,000 in favour of custom |
Three adjustments keep the comparison honest. First, transition: during the 6 months of development the existing subscription continues, adding EUR 40,500 on the custom side, which pushes break-even from about 23 to 28 months. Second, SaaS vendors often apply annual price indexation of 3 to 7%, not included here, which would widen the gap by EUR 15,000 to 35,000. Third, a SaaS also needs initial configuration, often EUR 10,000 to 25,000 with an integrator.
The criteria a spreadsheet does not show
Cost is only part of the decision. A CFO must also weigh the risks and flexibility of each option.
| Criterion | Off-the-shelf SaaS | Custom platform |
|---|---|---|
| Time to go live | 1 to 3 months | 5 to 8 months |
| Process fit | You adapt your processes to the tool | The tool follows your processes |
| Vendor lock-in | High: pricing, roadmap, end of life | Low if code and documentation are handed over |
| Data reversibility | Export often partial, to negotiate in the contract | You own the database |
| Specific changes | Rarely possible or expensive | EUR 600 to 750 per development day |
| Project risk | Low | Real: depends on scoping and steering |
| Security updates | Included | Included in maintenance, to be contracted |
Vendor lock-in is the most underestimated risk. A vendor acquisition, a 20% price rise or a discontinued module can upend your budget with no recourse. Conversely, custom projects mostly fail when scoping is rushed: plan 8 to 12 days of workshops before any development.
When to choose which option
SaaS remains the right choice if your activity is standard (accounting, payroll, general CRM), if you have fewer than 50 users or if you must be live within three months. Custom is justified above 100 users, when the process is a competitive advantage (job scheduling, complex contract management, specific pricing) and when the SaaS forces Excel workarounds. A middle path exists: keep a SaaS for standard functions and build only the differentiating module, for EUR 40,000 to 70,000.
Mini case study
Sophie, CFO of a technical services company in Amsterdam, equips 150 staff with a field service management tool. The shortlisted SaaS costs EUR 45 per user per month, or EUR 6,750 per month. The agency consulted prices the custom platform at EUR 120,000, delivered in 6 months, with EUR 1,500 per month for maintenance and hosting.
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Break-even calculation: cumulative custom cost = EUR 40,500 (current subscription during the project) + EUR 120,000 + EUR 1,500 per month after delivery. The SaaS accumulates EUR 6,750 per month. The lines cross around month 28. Over 5 years, Sophie saves about EUR 154,500 after transition, enough to fund two major upgrades a year. She requires in the contract the handover of source code, technical documentation and a reversibility clause.
FAQ
How much does a custom business platform for 150 users cost?
EUR 80,000 to 180,000 depending on complexity, with about EUR 120,000 for an operations management tool. Add 12 to 18% per year for maintenance and hosting.
From how many users does custom become cost-effective?
Against a SaaS at EUR 45 per month, the threshold is around 80 to 100 users over 5 years. Below 50 users, SaaS almost always remains cheaper.
How do you avoid dependence on the custom developer?
Require code ownership, a Git repository in your name, technical documentation and mainstream technologies. Another provider should be able to take over within 2 to 4 weeks.
What should you plan for SaaS reversibility?
A clause for full data export in an open format, free of charge, within 30 days of termination. Without it, a migration can cost EUR 15,000 to 40,000.
Is custom riskier?
Yes during the project, with possible overruns of 10 to 25% if scoping is weak. Delivering in 6 to 8 week increments limits that risk.
Let's scope your project. Share your user count, current subscriptions and key processes, and we will calculate your 5-year total cost and a first custom release from EUR 40,000. 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.
