How long does it take to build a mobile app?

A simple app MVP takes 8-12 weeks. A medium-complexity app with user auth, payment integration, and backend connectivity takes 3-5 months. A complex app with real-time features, offline support, and multiple user roles takes 5-8 months. These timelines assume one full-time dedicated developer. Adding a second developer doesn't halve the time but can reduce it by 30-40%.