The verdict in three sentences
The build cost of a custom business web app (60,000 to 150,000 EUR) is only 45 to 55 % of the total cost over 5 years. The true budget adds hosting, application maintenance (TMA), feature evolution and security — a multiplier of 1.8 to 2.2 on the initial build. Ignoring TCO means signing a quote thinking you pay 100,000 EUR while spending 200,000 EUR.
Breaking down the 5-year TCO
Total cost of ownership (TCO) sums every expense from the first sprint to year 5 of operation. Here is a 2026 order-of-magnitude grid for a mid-size business app (20 to 40 screens, 50 to 150 users) built in New York.
| Line item | 2026 amount (EUR) | Basis |
|---|---|---|
| Initial build | 90,000 | 25-40 screens, 4-6 months |
| Hosting + infra (5 yrs) | 27,000 | 5-15 %/yr of build |
| Maintenance + security (5 yrs) | 81,000 | 18 %/yr of build |
| Feature evolution (5 yrs) | 60,000 | 2 releases/yr at 6,000 EUR |
| Third-party licenses + monitoring | 12,000 | ~200 EUR/month avg |
| 5-year TCO | 270,000 | build x 3.0 |
Here the build is only 33 % of real TCO. Even excluding evolutions (a choice), the unavoidable base (build + hosting + maintenance) already reaches 198,000 EUR, i.e. build x 2.2.
The 4 line items that blow the budget
| Line item | Common trap | 2026 range |
|---|---|---|
| Maintenance | Quoted at 8 % instead of 18 % | 15-20 %/yr of build |
| Hosting | Under-sized at launch | 300-2,500 EUR/month |
| Security | No audit budgeted | 4,000-12,000 EUR/yr |
| Technical debt | No refactoring planned | 10-15 % of dev time |
| Reversibility | Vendor lock-in | 5,000-20,000 EUR exit |
A maintenance quote at 8 %/yr is a red flag: it funds bug fixes, not security or dependency updates. In 2026, a framework left unpatched for 18 months exposes known vulnerabilities and raises the cyber-insurance premium.
Custom vs SaaS: when TCO decides
| Criterion | Custom | Vertical SaaS |
|---|---|---|
| Year 1 cost | 90,000 EUR | 12,000-30,000 EUR |
| Year 5 cost (cumulative) | 270,000 EUR | 90,000-180,000 EUR |
| Code ownership | Full | None |
| Process fit | Unlimited | Limited to config |
| Cost per user | Decreasing | Linear (per seat) |
Custom pays off once user count exceeds 80 to 120 seats, or when business logic fits no SaaS. Below that, SaaS almost always wins on 5-year TCO.
Mini case study
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Claire, CFO of a 140-employee industrial SME in New York, weighs a production-management SaaS at 24,000 EUR/yr (per seat) against a custom app. The SaaS costs 120,000 EUR over 5 years but cannot handle her 3 specific production lines. The custom build is quoted at 95,000 EUR; with realistic TCO (hosting 1,000 EUR/month, maintenance 18 %) she reaches 275,000 EUR over 5 years. The decision flips when she prices the 22 hours/week of Excel re-keying avoided: at 35 EUR/loaded hour, that is 40,000 EUR/yr saved, or 200,000 EUR over 5 years — custom turns strongly positive.
FAQ
What multiplier should I apply to the build to estimate 5-year TCO?
Use a factor of 2.2 to 3.0 depending on evolution intensity. A stable base with no new features stays near 2.2; an actively growing app reaches 3.0.
Is maintenance really mandatory?
Yes. Without it, dependencies age, vulnerabilities pile up, and any outage costs more as an emergency. Budget 15-20 %/yr of build, never below 12 %.
How can I reduce TCO without sacrificing quality?
Choose mainstream technologies (less debt), host on managed services (less ops), and prioritize evolutions by ROI rather than a fixed annual release. That can cut 15 to 25 % of TCO.
Is cloud more expensive than on-premise?
In 2026, managed cloud costs more per use but removes hidden operating costs (on-call, hardware, backups). For an SME with no ops team, it remains cheaper on full TCO.
Should I budget reversibility from the start?
Yes. Contractually require data export and code handover. An exit clause avoids a 5,000 to 20,000 EUR migration cost at end of life.
Let's scope your project. Give us your screen count, user count and target budget: we build your full 5-year TCO grid. 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.
