The verdict in three sentences
Estimating a business-app budget doesn't require being a developer: you break the project into epics and rate each by complexity. Multiply estimated days by a day rate of EUR 450-650 (EU agency range 2026), then add a risk buffer of 15-20%. You get an honest range — EUR 30,000-60,000 for a simple app, EUR 80,000-200,000 for a complex one — before you even consult.
Step 1: break into epics, estimate by complexity
An epic is a large functional block (authentication, dashboard, invoicing module...). For each you assign a complexity size mapped to a range of person-days. This method avoids finger-in-the-air quotes.
| Complexity | Description | Person-days | Cost (EUR 550/day) |
|---|---|---|---|
| S (simple) | Basic CRUD, 1 screen | 3 - 5 d | 1,650 - 2,750 |
| M (medium) | Business logic, filters | 8 - 15 d | 4,400 - 8,250 |
| L (large) | Workflow, roles, integrations | 20 - 35 d | 11,000 - 19,250 |
| XL (extra large) | Complex engine, real-time | 40 - 70 d | 22,000 - 38,500 |
An "invoicing with automatic reminders" epic is typically an L; a "recommendation engine" an XL.
Step 2: sum up, apply the day rate, add the buffer
Sum the epics, pick a realistic day rate by builder, then add the risk buffer. That buffer isn't padding: it absorbs technical surprises, spec back-and-forth and testing.
| App type | Total days | Low range (EUR 450) | High range (EUR 650) | + 18% buffer |
|---|---|---|---|---|
| Simple app | 60 - 90 d | 27,000 | 58,500 | 32,000 - 69,000 |
| Medium app | 100 - 160 d | 45,000 | 104,000 | 53,000 - 123,000 |
| Complex app | 180 - 300 d | 81,000 | 195,000 | 96,000 - 230,000 |
Timeline follows: budget roughly 1 developer per 20 person-days/month. A 160-day app mobilises 2 devs for ~4 months.
Mini case study
Marc, project owner in food processing in Amsterdam, wants a supplier-traceability app. He lists 6 epics: auth (M, 12d), supplier catalogue (L, 25d), batch entry (M, 14d), compliance dashboard (L, 22d), regulatory exports (M, 10d), notifications (S, 5d) = 88 days. At EUR 550: EUR 48,400, + 18% buffer = EUR 57,100. He consults three agencies with that figure in mind: two quotes land at EUR 54,000 and 61,000, confirming his scoping. The third at EUR 89,000 reveals a misunderstood scope — dismissed at once. Gain: negotiating as an equal.
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FAQ
Can I estimate without being technical?
Yes: the epics x complexity method is built for non-technical project owners. You get a range within plus or minus 25% of reality, enough to scope.
Which day rate should I use in Amsterdam in 2026?
Budget EUR 450-650/day for a quality agency. Below EUR 400, be wary of seniority or the team's real location.
Why buffer 15-20%?
Because no software project runs without surprises: evolving specs, technical dependencies, testing. Without a buffer you almost certainly overrun.
How do I tell if an epic is L or XL?
If it involves real-time, an algorithmic engine, or more than three external integrations, class it XL. When in doubt, size up: underestimating costs more than the margin.
Is a very low quote a good deal?
Rarely. A quote 30% below your other estimates usually signals a misunderstood scope that will explode mid-project.
Let's scope your project. Send us your epic list (even rough) and target budget, and we'll price each block by complexity. 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.
