The verdict in three sentences
A custom web app costs in Dublin in 2026 between 20,000 and 100,000 EUR, and the price follows from four drivers: number of screens, user roles, integrations and business complexity. A reliable estimate comes from a phased, priced breakdown rather than a global figure thrown out at random. The fixed-price vs time-and-materials choice shifts who carries the risk far more than it changes the total.
The four cost drivers
Each driver pushes the price up or down. Here is their quantified impact in 2026.
| Driver | Low | Medium | High |
|---|---|---|---|
| Number of screens | < 10 | 10 to 25 | > 25 |
| User roles | 1 | 2 to 3 | 4+ |
| External integrations | 0 to 1 | 2 to 3 | 4+ |
| Business complexity | simple CRUD | calculations, workflows | rules engine, AI |
| Budget impact | 20,000-35,000 EUR | 35,000-65,000 EUR | 65,000-100,000 EUR |
An app with 12 screens, 2 roles, 2 integrations and moderate workflows typically falls in the 45,000 - 60,000 EUR band.
Phased estimation method and fixed-price vs T&M
Estimating by phases makes the budget readable and fundable. Here is an example breakdown and a comparison of billing modes.
| Phase | Content | Share of budget | Timeline |
|---|---|---|---|
| Phase 0 - Scoping | specs, mockups, architecture | 8 to 12% | 2 to 3 wks |
| Phase 1 - Core | auth, data, 1 module | 40 to 50% | 6 to 9 wks |
| Phase 2 - Modules | business functions, integrations | 30 to 40% | 5 to 8 wks |
| Phase 3 - Testing/go-live | tests, fixes, deployment | 8 to 12% | 2 to 3 wks |
| Mode | Fixed price | Time & materials | |
| Price | fixed, set at scoping | 600 to 750 EUR/day | |
| Overrun risk | carried by the agency | carried by the client | |
| Scope flexibility | low | high | |
| Ideal if | well-defined need | evolving scope |
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Mini case study
Julie, sponsor of a field-service management app project in Dublin, is unsure of the budget. After scoping: 14 screens, 3 roles, 2 integrations (billing + mapping), moderate workflows. The phased estimate gives 52,000 EUR: 6,000 scoping, 24,000 core, 18,000 modules, 4,000 testing. Under fixed price she locks that figure; under T&M, at 680 EUR/day, the same scope is about 76 person-days. She picks fixed price for the core phase (clear need) and T&M for the modules (still-moving scope).
FAQ
Why such a wide range? Because the drivers make the workload vary fivefold; only scoping narrows the range to +/- 15%.
Is scoping paid? Usually yes (8 to 12% of the budget), but it is essential: it is what turns a range into a reliable quote.
Fixed price or T&M for a first project? Fixed price reassures when the need is clear; T&M suits you if you want to iterate and adjust continuously.
How do we avoid overruns? Split into phases, validate each deliverable, and keep a 10 to 15% reserve for unforeseen items.
How long does estimation take? A serious estimate requires 1 to 2 weeks of scoping workshops with your business teams.
Let's scope your project. Give us the number of screens, the roles, the integrations and your deadlines, and we will produce a priced phased estimate. 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.
