Direct answer
Platform choice changes the number more than any other single factor: a PWA (one codebase, no app-store review) is the cheapest path, cross-platform (React Native/Flutter, one codebase across iOS/Android) costs more, and fully native — built separately per platform — is the most expensive. Backend complexity, roles, integrations and AI features then shift the number within whichever platform you pick. An App Scope conversation, starting with the platform decision, gives an honest range.
Platform choice is the single biggest cost driver
A PWA is the cheapest path (one codebase, no app-store review). Cross-platform (React Native/Flutter) costs more but still shares one codebase across iOS/Android. Fully native, built separately per platform, is the most expensive — see PWA vs Native vs Cross-Platform for when each is actually justified.
What drives cost within any platform choice
Backend and API complexity (see What Backend Does a Mobile App Need?), number of user roles, third-party integrations, and whether AI features are included — the same factors that drive web application cost apply here.
App-store review and submission
Native and cross-platform apps need App Store / Google Play submission and review, which adds time (not usually large direct cost) that a PWA skips entirely.
How to get a real number
Through an App Scope conversation — platform choice alone can shift the estimate several times over, so a generic number without that decision made first wouldn't be honest.
Questions
How much does cross-platform app development cost compared to native?+
Less than native, since one React Native or Flutter codebase covers both iOS and Android — native means building and maintaining two separate codebases, which is the more expensive path.
Is hybrid app development cheaper than native?+
Generally yes, for the same reason as cross-platform: one shared codebase costs less to build than two fully native ones — the actual gap still depends on backend complexity, roles and integrations.
Is a PWA always the cheapest option?+
Usually yes for the initial build — though if it later needs to be rebuilt natively, the two costs together can exceed starting native, so factor in the likely long-term path too.
Does this include ongoing maintenance?+
No — app-store fee cycles, OS updates and ongoing maintenance are typically scoped separately from the initial build.
Can I start cheaper and upgrade platform later?+
Yes — starting with a PWA or cross-platform build and moving to native later (if justified) is a common, sensible path.