Why most cost estimates are wrong

The cost to build a B2B mobile app in 2026 ranges from 40,000 to 400,000 euros depending on scope, integrations, and team structure. That range is too wide to be useful on its own, so this post breaks it down by phase and explains what drives the number up.

Discovery and design (5,000-25,000 euros)

Discovery defines the spec the rest of the project executes against. For a focused B2B app — a field-service tool, an internal CRM extension, an inspection workflow — discovery and design runs 5,000 to 15,000 euros over two to four weeks. For a multi-stakeholder system with several integrations and complex permissions, expect 15,000 to 25,000 euros over four to eight weeks. Skipping this phase is the single most expensive false economy in the industry. Teams that skip discovery rebuild the same screens twice.

Core mobile development (25,000-200,000 euros)

Mobile development cost depends primarily on three things: scope of features, native vs cross-platform, and quality bar. A focused B2B app with 10-15 screens, one platform, and basic integrations runs 25,000 to 60,000 euros over two to four months. The same app on both iOS and Android natively roughly doubles the cost. A cross-platform build (Flutter or React Native) lands somewhere in between, often 1.5x the single-platform native cost.

Backend and integrations (10,000-100,000 euros)

If the app needs new backend, expect 10,000 to 40,000 euros for a focused API with a database, identity, and admin tools. If it integrates with an existing ERP, CRM, or inventory system, integration costs run 10,000 to 60,000 euros per major integration depending on the API quality of the partner system. SAP integrations cost more than Stripe integrations for predictable reasons.

QA, security, and pre-launch (5,000-30,000 euros)

QA on a B2B mobile app is not optional. Realistic budget is 15-25% of build cost for proper test coverage, manual testing on actual devices, security review, and pre-launch hardening. Teams that skip this phase ship apps that work for the demo but fail in customer hands.

App Store and Play Store setup (1,000-5,000 euros)

First-time Apple Developer accounts, Google Play Console setup, MDM integration if the app deploys via enterprise distribution, and store listing optimization. Often underestimated because it does not feel like engineering work. The MDM piece in particular can take a week if your client uses Microsoft Intune or VMware Workspace ONE.

Maintenance and operations (15-25% of build cost per year)

The line item teams forget. Operating system updates, library updates, store policy changes, security patches, and minor feature work. Plan for ongoing investment of 15-25% of the build cost annually. Apps without this budget rot within 18 months.

What drives cost up

Unusual integrations with legacy systems. Strict regulatory requirements (medical, financial). Real-time features (chat, live tracking) that demand backend complexity. Offline mode with sync. Multi-language with right-to-left support. Custom design with bespoke components rather than standard UI patterns.

What keeps cost down

A clear, scoped MVP. Single platform first, second platform after validation. Using existing identity (SSO with what the company already has). Reusing your existing backend rather than building new. Standard UI patterns rather than custom design language.

Realistic B2B mobile app scenarios

Field inspection app for 50 users, one platform, simple sync: 40,000-70,000 euros total over four to five months. Multi-platform sales-enablement app integrated with Salesforce: 90,000-160,000 euros over six to nine months. Production-grade B2B mobile app with offline support, custom backend, and SAP integration: 180,000-350,000 euros over nine to twelve months.

Get a fixed-price quote, not an estimate

For B2B mobile work, insist on a fixed-price quote against a written specification. Time-and-materials contracts on mobile apps almost always exceed estimates by 30-60%. A studio that knows the work can give you a fixed price because they have built similar systems before. If they cannot, they have not.