WPF or WinUI 3? Comparing options and migration costs

If your development partner recommends moving from WPF to WinUI 3, clarify one thing before you approve the quote: what will work better for your business after the change? Will employees find their tasks easier? Will you be able to add the features you need? Will the team find it easier to develop the application further?

Keep developing your WPF application if it meets your business needs and its problems can be fixed without replacing the entire interface. Consider WinUI 3 for a new Windows application or a substantial redesign of the screens and how people use them. For an application already in use, you also need to account for the cost of moving existing features, testing them and rolling out the update to users.

WPF vs WinUI 3: differences that matter to your business

WPF, short for Windows Presentation Foundation, and WinUI 3 are used to build Windows application interfaces: windows, forms, tables and buttons. WinUI 3 is part of Windows App SDK, Microsoft's set of tools for Windows applications. WPF runs on both .NET Framework and modern .NET, so the name WPF alone does not mean an application uses an outdated platform.

Consideration	WPF	WinUI 3
Developing an existing WPF application	You can keep the current screens and improve selected parts of the application.	The interface needs to be moved or rebuilt, and its features need to be tested.
Building a new Windows application	The choice depends on the features you need, the components available and the team's skills.	Microsoft recommends WinUI 3 for new applications built specifically for Windows. You still need to assess whether it fits your project.
Adding selected newer Windows features	Windows App SDK features can be added without replacing WPF, provided the project meets the requirements.	Uses Windows App SDK. Check whether the features you need are available on the Windows versions your customers use.
Complex tables and other screen elements	When updating the application, check that existing components still work correctly.	Not every WPF element has a direct equivalent; some require replacements or additional work.
Running on other operating systems	WPF alone does not provide a version for macOS or Linux.	WinUI 3 alone does not provide a version for macOS or Linux either.

Microsoft's recommendation for new projects is explained in the WinUI 3 documentation. The Windows App SDK documentation for existing projects explains how features can be added while keeping WPF.

Is WPF still supported?

Microsoft still supports WPF on modern .NET. You do not have to switch to WinUI 3 to continue developing a WPF application. Microsoft's modernization guide also covers updating .NET and adding features while retaining the existing interface.

You do need to check the .NET version and additional components your application uses. An older version may need an update even if you stay with WPF. Your development partner should explain exactly what needs to change and why.

Will WinUI 3 make a WPF application faster?

Switching to WinUI 3 does not guarantee that the whole application will run faster. First, you need to find out what causes the delays.

If an employee has to wait for an order to open, the problem may involve retrieving, processing or displaying the data. Replacing the screens alone will not shorten the wait for another system to respond. If the delay occurs when a large table is displayed, it is worth examining how that table works.

Before promising better performance, your development partner should measure the same task in both solutions using comparable data and hardware. That result gives you a basis for judging whether the proposed change will help users.

When does migrating from WPF to WinUI 3 make sense?

Consider migration when the changes you need affect a substantial part of the interface. For example, if a new way of handling orders requires most screens to be reorganized, WinUI 3 may be one option to compare with rebuilding them in WPF. In either case, the business should understand which user tasks will become easier and how much work the change involves.

If the problem is a single awkward form, start by comparing the cost of improving it in the existing application. The same applies to a missing feature: first establish whether it can be added to WPF.

For a larger redesign, the components available also matter. A complex table, printing or the way multiple windows behave may need a different approach. Microsoft describes the differences between WPF and WinUI 3 that need to be accounted for in the scope of work.

What determines the cost of migrating from WPF to WinUI 3?

The number of screens alone is not enough to estimate the work. A simple form takes a different amount of effort from a table with filtering, export and printing. Connections to other systems and the way the application is installed also affect the cost.

The quote should cover:

• Moving the features users need - including printing, keyboard shortcuts, permissions and error handling.
• Components and connections to other systems - what can be kept, what must be bought or built, and how connections to devices will be tested.
• Testing and rollout - checking users' everyday tasks, installing the application on their computers and planning how to return to the previous version. If the way data is stored changes, returning to the old version also requires checking data compatibility.
• Work during the transition - maintaining the old version, employees' time for testing and any training they need. Agree which new features will be developed during migration and which will have to wait.

The importance of testing is clear in our work on modernizing the TimeCamp desktop application, which is built in C++ and wxWidgets. At Software Logic, we modernize selected parts while continuing to develop features. Before a release, we test time tracking and project features. A modernization budget needs to include this work: users still need to get their day-to-day work done after the change.

How to test the choice before committing to a larger budget

Before commissioning a full migration, you can have part of the application built in WinUI 3. It should cover an important user task and elements that may be difficult to move. If employees mainly work with a complex table, that will be a more useful test than a simple login window.

For example, in an order management application, the trial might involve finding a document, changing its data, saving it and printing it. The acceptance criteria should define the correct result, an acceptable completion time, error handling and installation on a user's computer.

After the trial, your development partner should be able to explain what can be moved, what needs additional work and how this affects the estimate. If the benefits do not justify the migration cost, you can stay with WPF and spend the budget on features users need.

What to commission first

For the first conversation, prepare a description of the tasks causing problems, a list of planned features and any limits on how you can roll out an update. You do not need to identify the .NET version or compile a list of components yourself - your development partner can check these during the review.

As part of our software modernization work, Software Logic helps you assess which parts of an application are worth keeping and where changes are needed. The first stage should give you a clear scope of work and the reasons for it, acceptance criteria and a basis for an estimate. With that information, it is easier to decide whether to keep developing in WPF or move to WinUI 3.