What Does a Custom Web Application Cost in 2026?

TL;DR: Custom web applications for Belgian SMEs range from €5,000 for simple tools to €50,000+ for complex systems. The price depends on functionality, technical complexity, integrations, and development time. Beyond development costs, also budget for annual hosting (€200-€1,000) and maintenance costs (10-20% of the development budget). A thoughtful approach and clear requirements keep costs manageable.

Which Factors Determine the Price of a Custom Web Application?

At LUNIDEV, we analyse each project based on concrete factors that directly impact development time and thus the costs. The biggest cost drivers are:

Functional complexity forms the basis of every price calculation. A simple booking system for a local service provider requires less development time than an extensive ERP system with inventory management. Every functionality - from user management to reporting modules - requires design, programming, and testing.

Technical integrations can significantly increase costs. Connecting with existing systems like accounting packages (Exact, Sage), payment systems (Mollie, Stripe), or external APIs requires specialist knowledge and additional testing work. As a developer, I see that integrations often consume half of the development time.

User experience design determines not only how your application looks but also how intuitively it works. A professional design with user-friendly interfaces costs more than a basic implementation but significantly increases adoption by your team.

Scalability and performance are investments for the future. An application that can handle growth and remains fast under increased load requires a more thoughtful architecture and better hosting infrastructure.

What Are the Hidden Costs in Web Application Development?

Many entrepreneurs focus only on development costs, but there are important additional costs that can impact your budget.

Project management and communication often make up 15-25% of total project costs. This includes requirement analysis, regular updates, feedback sessions, and change management. At LUNIDEV, we transparently build this into our quotes.

Testing and quality assurance are essential for a stable application. Beyond functional tests, you need to budget for performance tests, security audits, and user testing. A thorough testing phase prevents costly bugs after delivery.

Training and implementation are often forgotten in budgets. Your team needs to learn to work with the new application, data must be migrated, and there may be necessary adjustments to existing processes.

Unforeseen changes during development can increase costs. That's why we work with clear change procedures and transparent communication about extra work on every project.

How Do I Calculate the ROI of a Custom Web Application?

A custom web application is an investment that should deliver measurable benefits for your business. The ROI calculation helps you determine if the investment is justified.

Time savings are often the most concrete benefit. If your team spends hours daily on manual processes, automation can free up this time for valuable activities. Calculate how many hours per week you save and multiply this by your hourly rate.

Error reduction delivers both time and cost savings. Automatic data processing prevents human errors that can be expensive to correct later.

Scalability becomes important as your business grows. A good system can process more work without requiring proportionally more staff.

Competitive advantage is harder to quantify but can be significant. A unique application that differentiates your service can attract new customers and better serve existing ones.

Custom Development Versus Off-the-Shelf Solutions

The choice between custom development and existing software has a major impact on both initial costs and future flexibility.

Off-the-shelf solutions have lower startup costs. SaaS platforms often require monthly subscriptions between €50-€500, depending on functionality and number of users. These solutions are quick to implement and have proven functionalities.

Custom development has higher initial costs but offers complete control and customisability. You pay once for development and have no ongoing license costs for external software.

Hybrid approach combines both advantages. We often build custom interfaces on top of existing services, which limits development costs while still providing a tailored user experience.

For our own project LUNIKIDS, for example, we chose a custom frontend with existing educational content APIs, which significantly reduced development time and costs.

Maintenance and Hosting Costs After Delivery

A web application has ongoing costs after delivery that you must budget for a realistic total calculation.

Hosting and infrastructure costs vary from €200 per year for simple applications to €1,000+ for complex systems with high performance requirements. Cloud hosting scales with your usage but requires monitoring to avoid unexpected costs.

Security updates and patches are not optional. Regular updates keep your application safe against new security threats. Budget for at least four updates per year.

Functional extensions often emerge after practical use. Users discover new needs or processes change. Budget annually 10-20% of your original development costs for improvements.

Technical support and bug fixes are inevitable, especially in the first year. A good developer offers a warranty on their work, but more complex problems can involve additional costs.

Saving on Development Costs Without Quality Loss

Smart choices during the planning phase can significantly save on your total project costs without compromising quality.

MVP approach (Minimum Viable Product) starts with core functionalities and expands later. This spreads costs over time and lets you learn from user feedback before investing in advanced features.

Reusing existing components reduces development time. At LUNIDEV, we have a library of tested components that we adapt for new projects, which lowers development costs.

Clear requirements prevent costly changes during development. Invest time in working out your wishes before development begins. An extra day of planning often saves weeks of development time.

Technology choices influence both development speed and future maintainability. Modern frameworks like React and Next.js that we use have a large community and many available libraries.

Realistic Budgets for Different Application Types

Based on our experience as developers, we can provide indicative budget ranges for common application types.

Simple business tools like time tracking, customer management, or simple booking systems start from €5,000-€15,000. These have limited functionality but cover specific business needs well.

Extended business applications with multiple modules, user roles, and reporting typically cost €15,000-€35,000. Think inventory management, project management tools, or customer portals.

Complex enterprise solutions with integrations, advanced workflows, and high performance requirements can cost €35,000-€75,000+. These systems often replace multiple existing tools.

Innovative platforms with unique functionalities or new technologies require more research and experimentation, which can increase costs to €50,000+.

Questions for an Accurate Price Quote

Asking the right questions to potential developers ensures realistic quotes and prevents surprises during the project.

Functional questions about what your application should do: "Which processes do you want to automate?", "How many users will work with it?", "What data do you need to store and edit?"

Technical questions about integrations: "Does the application need to connect with existing systems?", "Which external services do you currently use?", "Are there specific security requirements?"

Project questions about approach: "What does your development process look like?", "What's included in the quote?", "How do you handle changes?"

Support questions about after delivery: "What warranty do you offer?", "What do updates and maintenance cost?", "How quickly can you solve problems?"

At LUNIDEV, we start every project with a thorough intake to clarify all aspects before preparing a quote.

Frequently Asked Questions

Why are custom web applications more expensive than websites?

Custom web applications have more complex functionality than informational websites. They process data, have user accounts, contain business logic, and often require integrations. This demands more development time, more extensive testing, and ongoing maintenance.

Can I have a web application developed in phases to spread costs?

Yes, a phased approach is often wise. Start with an MVP (Minimum Viable Product) with core functionalities and expand based on user experiences. This spreads costs over time and reduces risks.

What happens to my application if the developer stops operating?

Always ask about ownership of the source code and documentation. At LUNIDEV, you get complete ownership of your application, including all code and access to hosting. This way you're never dependent on one party.

How much does it cost to have an existing application modified?

Changes typically cost €75-€125 per hour, depending on complexity. Small adjustments can take several hours, while new modules require weeks of development time. A good analysis upfront prevents surprises.

Is cloud hosting more expensive than own servers for web applications?

Cloud hosting starts cheaper (€20-€100/month) but can become more expensive with intensive use. Own servers have high startup costs but lower variable costs. For most SMEs, cloud hosting is more cost-effective due to lower management overhead.