The verdict in three sentences
Realistic 2026 timelines range from 4-8 weeks for a brochure site to 16-32 weeks for a business platform, and it is not the developers who stretch things most, it is client-side validations and content. A credible schedule is reasoned by work packages with acceptance milestones, not a single date. A launch delay rarely costs zero: tied-up cash, postponed campaigns, missed seasonality add up to thousands of euros fast.
Timeline ranges by project type (2026)
These ranges assume a validated requirements document and an available client contact. They stretch mechanically with vague scope or slow validations.
| Project type | Realistic timeline | Key milestones | x factor if complex |
|---|---|---|---|
| Brochure site 5-10 pages | 4-8 weeks | Mockup, build, acceptance | 1.5 |
| Corporate site + CMS | 8-14 weeks | Structure, design, content, acceptance | 1.6 |
| Standard e-commerce | 10-20 weeks | Catalogue, payment, logistics | 1.7 |
| Business platform | 16-32 weeks | Framing, sprints, acceptance, deploy | 2.0 |
| Mobile app | 14-28 weeks | UX, dev, stores, acceptance | 1.8 |
| Revamp + migration | 12-24 weeks | Audit, data reuse, SEO | 1.9 |
What stretches the schedule (and by how much)
Delays rarely come from code alone. Here are the most common factors and their typical calendar impact.
| Delay factor | Typical impact | How to control it |
|---|---|---|
| Content delivered late | +2 to 6 weeks | Content plan from kickoff |
| Slow validations (multi-decision) | +1 to 4 weeks | One approver, fixed deadline |
| Scope creep mid-project | +10 to 40 % | Prioritised RFP, freeze after framing |
| Third-party integrations (ERP, payment) | +2 to 8 weeks | Test APIs early |
| Late client acceptance | +1 to 3 weeks | Acceptance by lot, not at the end |
| Client team unavailability | +2 to 5 weeks | Appoint a project referent |
Typical schedule by work package
A 24-week platform project typically breaks down as: framing and UX (weeks 1-4), design (weeks 3-7), development in sprints (weeks 6-18), integrations (weeks 12-20), acceptance and fixes (weeks 18-22), deployment and training (weeks 22-24). Overlapping packages is normal and healthy; that is what distinguishes a realistic schedule from a chain of sequential phases that simply add up.
Mini case study
Thomas, head of a 40-employee trading SME in Bordeaux, wants to launch his B2B e-commerce store before the September high season. He approaches an agency in May demanding delivery in 8 weeks.
The agency shows him the scope (800-SKU catalogue, payment, ERP connection) implies a realistic 16 weeks. Forcing 8 weeks would have shipped an incomplete site with no serious acceptance. He accepts phasing: catalogue + payment MVP in 10 weeks (for the season), then ERP integration in 6 weeks. Cost of a launch delay estimated at around 3,500 EUR per week (missed season, cash). Phasing wins him the season without sacrificing quality, where a failed launch would have cost over 20,000 EUR in lost sales.
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FAQ
Why do agencies give ranges rather than a firm date?
Because 30 to 50 % of the timeline depends on the client: content, validations, availability. A firm date only makes sense after framing and if client commitments are met.
Can you speed up a project by paying more?
Up to a point: adding developers to a poorly framed task often slows things down (Brooks's law). Better to phase and ship an MVP early than inflate the team at the end.
How much time should acceptance take?
Between 10 and 20 % of project duration. On a 20-week project, budget 2 to 4 weeks of acceptance, ideally by lot rather than concentrated at the end.
What stretches an e-commerce project most?
The catalogue (product sheets, photos, prices) and payment/logistics integrations. An unprepared 800-SKU catalogue alone can add 4 to 6 weeks.
How do you cost a delay?
Add the lost income (deferred sales or leads), the tied-up cash and the fixed costs running with no revenue. On a seasonal e-commerce, one week of delay often exceeds 3,000 EUR.
Let's scope your project. Give us your target date and scope: we build a realistic package schedule with acceptance milestones and, if needed, an MVP to hit your deadline. 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.
