Mobile timelines slip for two reasons that have nothing to do with engineering skill: nobody agreed on scope before the estimate, and nobody budgeted for the app store. Both are avoidable, and both are why the honest answer is a range tied to project size rather than a single number.
Timeline by project size
These assume a cross-platform build covering iOS and Android from one codebase, which is what most projects actually need. A fully native app built separately for each platform takes longer, because it is effectively two builds.
| Tier | What it typically includes | Timeline |
|---|---|---|
| Focused | Single user flow, basic auth, one or two core screens | ~3 weeks |
| Standard | Multiple flows, push notifications, a couple of integrations | ~5 weeks |
| Substantial | Offline sync, payments, complex permissions, admin backend | ~8 weeks |
Where the weeks actually go
Every project moves through the same stages regardless of size. Scoping the workflow and locking a fixed price takes a few days. Architecture and screen flows take a few more, and this stage matters more on mobile than on web, because decisions about offline behavior and data sync are expensive to reverse later. The build itself is where project size shows up, running from about two weeks for a focused app to six or more for a substantial one, with a shared build you can install and try throughout. QA runs on real devices, not just simulators, before submission.
The store review wildcard
App store review adds timeline risk that has nothing to do with your build quality. Apple's review can take anywhere from a day to a couple of weeks depending on what the app does and how busy their queue is. We build a submission buffer into every mobile timeline for exactly that reason, and a first release that touches payments, health data or anything else Apple reads closely deserves extra slack.
If your launch is tied to a real-world date, an event, a campaign, a season, work backwards from it and leave the review buffer intact. Submitting a week before a hard deadline is how launch dates get missed by apps that were finished on time.
What stretches a mobile timeline
- Offline-first architecture. Syncing local data with a server reliably is genuinely hard and adds real time.
- Hardware integrations. Bluetooth devices, AR, or background sensors each bring their own debugging cycle on real hardware.
- In-app purchases or subscriptions. Store billing APIs are finicky, and testing them properly takes longer than people expect.
- Slow feedback turnaround. If review rounds sit for a week, the calendar stretches even though the work itself has not grown.
Want a timeline for your specific app instead of a general range?
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