The verdict in three sentences
An internal web app replacing critical spreadsheets costs between 20,000 and 60,000 EUR (excl. tax) in 2026, depending on the number of processes and users. The trigger is never aesthetics: it's the moment Excel becomes an operational risk — corrupted files, competing versions, broken formulas, no traceability. A dedicated app brings user permissions, a single source of data and reliability that pays for itself in recovered hours.
Signs Excel has hit its limits
Before pricing, check how many of these signs apply to you. Each is a measurable hidden cost.
| Sign | Symptom | Estimated monthly hidden cost |
|---|---|---|
| Multiple versions of the same file | "Which one is right?" | 4-10 h of reconciliation |
| Broken formulas / silent errors | Wrong figures undetected | Risk of bad decisions |
| No access rights | Everyone sees/edits everything | GDPR & leak risk |
| No history | Can't tell who changed what | Internal disputes |
| Re-entry between files | Manual copy-paste | 6-15 h/month |
| Multi-editor locking | File locked | Waiting & frustration |
Three or more signs checked: the web app is no longer a comfort, it's an operational compliance fix.
What the app costs by scope
The budget depends on the number of modules, users and permission complexity. Here are the 2026 ranges.
| Scope | Example | Budget (EUR excl. tax) | Timeline |
|---|---|---|---|
| Simple app | 1 process, CRUD + basic roles | 20,000 - 30,000 | 6-10 wks |
| Standard app | 2-3 processes, fine roles, exports | 30,000 - 45,000 | 10-14 wks |
| Advanced app | 4+ processes, 1 integration, dashboards | 45,000 - 60,000 | 14-20 wks |
Data migration from your Excel files (cleaning, deduplication, import) typically represents 3,000 to 8,000 EUR and determines a successful launch.
User permissions and reliability: the real deliverable
Where Excel lets everyone do everything, a web app sets roles: who sees, who edits, who approves. Every action is timestamped and traced, which removes internal disputes and secures your personal data under GDPR. Input validation (required fields, controlled formats) eliminates errors at the source, unlike an Excel formula that can break with nobody noticing.
Mini case study
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Sophie, operations director of a services SME in Nantes (35 employees), ran scheduling, leave and client billing across five shared Excel workbooks. Every month, roughly 18 hours went to reconciling versions and fixing re-entry errors. The custom web app cost 34,000 EUR (excl. tax), migration included, delivered in 12 weeks. Gain: 16 hours/month recovered (about 9,600 EUR/year of capacity), zero billing discrepancies since, and a full audit trail. Estimated payback around 26 months, excluding the compliance benefit that's hard to quantify but real.
FAQ
Can we keep Excel for some tasks?
Yes, Excel stays excellent for one-off analysis and prototyping. You drop it for recurring, multi-user, critical processes where the shared file becomes a risk rather than a tool.
How much does migrating our data cost?
Between 3,000 and 8,000 EUR in 2026 depending on file cleanliness. Well-structured data migrates fast; spreadsheets full of exceptions and merged cells need prior cleaning you must budget for.
Will our teams know how to use it?
A good internal app is simpler than Excel for the end user: guided forms, no formulas. Expect one training session and adoption within a few days for most teams.
Does the app work offline or on mobile?
Depending on need. A responsive web version is enough in most cases; an offline mode (PWA) is possible but adds 15 to 30% to the budget. You enable it only if fieldwork justifies it.
What if our needs evolve?
A custom app is built to grow by adding modules. Budget 12 to 18% per year for maintenance covering changes, fixes and version upgrades.
Let's scope your project. List the Excel files costing you time and the number of users involved, and we'll price the app with the best return. 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.
