"How long will it take?" is the second question founders ask, right after cost. Honest answer: it depends on scope, feedback speed, and how many integrations you pile into version one. Here is a phase-by-phase breakdown based on Flutter projects I deliver.
Phase 1: Discovery (3–7 days)
Clarify users, core flows, success metrics, and version-one boundaries. Output: written scope, feature list, rough wireframes or flow diagram. Skipping this phase adds weeks later through rework.
Phase 2: Design (1–3 weeks)
Figma screens for key flows, component library, clickable prototype for founder approval. Simple apps: one week. Complex apps with many states and roles: three weeks. Design approval gates development — do not parallelise blindly or you pay twice.
Phase 3: Development
Simple (5–8 screens, no backend): 2–3 weeks
Standard (auth, API, 10–15 screens): 4–6 weeks
Complex (payments, chat, admin): 8–12+ weeks
Weekly demos on real devices keep alignment. Budget one sprint for "unknown unknowns" — API quirks, store policy surprises, third-party SDK issues.
Phase 4: QA and polish (1–2 weeks)
Device testing, edge cases, performance passes, accessibility basics, crash fixes. Founders often underestimate this — a feature-complete app is not a shippable app.
Phase 5: Store submission (3–10 days)
Prepare assets, privacy labels, demo accounts for reviewers, build signing, submit. Apple review: often 1–2 days, sometimes longer if rejected once. Google: variable, especially for new developer accounts.
What slows projects down
- Founder feedback latency — multi-day gaps between demos
- Scope additions without timeline adjustment
- Third-party API documentation gaps
- Incomplete content (copy, images, legal pages)
- Parallel branding or website work without decision owners
How to hit your target date
Freeze scope, assign one decision-maker, respond within 24 hours on blockers, and cut features before cutting quality. A good developer will tell you when a date is unrealistic — believe them early, not at the deadline.