The verdict in three sentences
Below 30 users and on a standard process, a market SaaS is almost always the best choice. Above 50 users, or when your process is a competitive advantage, custom software becomes competitive over a 3 to 5 year horizon. The right call is made not on entry price but on 5-year TCO and how specific your business really is.
The decision grid: 5 criteria that settle it
Four factors outweigh the rest: number of users, process specificity, required integrations and data sensitivity. Score each, then look at the total.
| Criterion | Favours SaaS | Favours custom |
|---|---|---|
| Number of users | < 30 users | > 50 users |
| Process specificity | Standard (accounting, CRM) | Unique, differentiating |
| Integrations | 1 to 2 tools | 4+ internal systems |
| Sensitive data | Low stakes | GDPR/regulated sector |
| Usage horizon | < 3 years | > 5 years |
Tick three "custom" columns or more and the TCO almost always tilts that way.
5-year TCO: the tipping point in numbers
SaaS at EUR 60/user/month feels painless at 10 people (EUR 7,200/yr). The same tool at 100 people costs EUR 72,000/yr, i.e. EUR 360,000 over 5 years, before annual increases of 10 to 15%.
| Users | SaaS 5 yrs (EUR 60/user/mo) | Custom 5 yrs (dev + maintenance) | Winner |
|---|---|---|---|
| 10 users | EUR 36,000 | EUR 70,000 | SaaS |
| 30 users | EUR 108,000 | EUR 90,000 | Tie |
| 50 users | EUR 180,000 | EUR 110,000 | Custom |
| 100 users | EUR 360,000 | EUR 150,000 | Custom |
| 200 users | EUR 720,000 | EUR 210,000 | Custom |
Custom has a fixed cost (development amortised) while SaaS is linear in seats. That slope creates the tipping point.
Recommendation per case
- SME < 30 users, standard process: SaaS, no hesitation. Immediate time-to-value.
- SME/mid-cap 30-50 users, specific process: mandatory TCO audit, often hybrid (SaaS + custom module).
- Mid-cap > 50 users, business advantage: custom, or at minimum a proprietary layer over APIs.
- Ultra-sensitive data: self-hosted custom, whatever the user count.
Mini case study
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Mark, COO of a 120-staff logistics mid-cap in London, pays 3 business SaaS tools at EUR 55/user/month for 90 active users, i.e. EUR 4,950/month (EUR 59,400/yr). Over 5 years, at +12%/yr, the bill tops EUR 375,000. A custom app unifying the 3 tools is quoted at EUR 95,000 development + EUR 14,000/yr maintenance, i.e. EUR 165,000 over 5 years. Net saving: EUR 210,000, payback in 22 months, and a process built for his business.
FAQ
From how many users does custom become worthwhile?
The tipping point usually sits between 30 and 50 users for SaaS at EUR 50-70/user/month. Below it SaaS wins over 5 years; above it, custom's fixed cost takes over.
How much does a custom business app cost in 2026?
Budget EUR 25,000 to 100,000 for a business application depending on scope, plus 10 to 18% of the initial cost per year for maintenance and evolutions.
Is custom riskier?
The main risk is project management, not technology. Slicing into lots delivered every 2 to 3 weeks and an MVP in 8 to 12 weeks sharply reduce risk.
Can I combine SaaS and custom?
Yes, often optimal: keep standard SaaS (payroll, accounting) and build only the differentiating module, connected via API. Entry cost cut by 2 to 3x.
What happens to my SaaS if the vendor raises prices?
You absorb the hike or migrate, with an exit cost. Custom makes you the code owner and removes that pricing dependency.
Let's scope your project. Give us your user count, current tools and an indicative budget: we return a costed 5-year SaaS vs custom TCO comparison. 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.