UX vs UI: what is the difference, and which do you need?

Picture two versions of the same booking page. The first is beautiful: large photos, elegant typefaces and a soft colour palette. But to book, the customer has to go through seven screens, and the date picker only works with a mouse. The second looks dull, but the customer is done in 40 seconds. The first has a UX problem, the second a UI problem. Both cost you bookings. That is the simplest way to understand the difference between UX and UI, and it is why you need both.

The terms are often mixed up, and “UX/UI” appears on so many job ads and quotes that it can sound like one thing. Searches for “ui ux designing” run at approximately 300,000 a month globally and are rising, so you are not alone in asking. In this guide we separate the two disciplines, show them in a concrete flow and explain what to ask for when you buy design.

What is the difference between UX and UI design?

A useful rule of thumb: UX is the skeleton and nervous system, UI is the skin and face. A product with strong UX and weak UI works, but feels cheap and loses trust. A product with strong UI and weak UX looks good in the presentation and disappoints in use. The best products are built by people who understand both and work closely with developers.

What is UX design, and what does it involve?

UX design starts with questions: who are the users, what are they trying to achieve and what gets in the way? The answers come from interviews, observation, data from the existing product and tests of early sketches. From that, the structure is designed: which pages and screens exist, what goes where and in which order the steps come. If you want to see a UX designer’s work day by day, we describe it in what a UX designer does.

• User research: interviews, surveys and observing real users.
• User journeys: mapping every step from need to solved task.
• Information architecture: menus, navigation and how content is grouped.
• Wireframes: simple sketches of each screen without colour or images.
• Prototypes and user testing: clickable versions tested with five to eight users.
• UX writing: button labels, error messages and help text that guide the user.

What is UI design, and what does it consist of?

UI design takes the structure from UX and gives it form. It covers visual hierarchy so the eye sees the most important thing first, typography that is easy to read on a small screen, colours with enough contrast to meet WCAG 2.1 AA, and components that behave the same everywhere. Good UI is also brand: the same booking can feel like a luxury clinic or a practical tradesperson, depending on colours, images and tone.

• Layout and grid that work from mobile to large screens.
• Typography, sizes and line spacing.
• A colour palette with contrast requirements and states such as error, success and disabled.
• Buttons, fields, cards, tables and other components with every state.
• Icons, illustrations and image style.
• Micro-interactions that confirm actions and show progress.

One area where UX and UI meet is accessibility. Since 28 June 2025 the European Accessibility Act has applied in Denmark to e-commerce and other consumer services, and WCAG 2.1 AA is the practical target. Some requirements are UX: a logical order, clear error messages and everything usable by keyboard. Others are UI: contrast, text size and visible focus indicators. Micro-enterprises are exempt from the service requirements, but good accessibility makes the product easier for everyone. Read more in our guide to the accessibility act for websites.

UX vs UI in practice: an example from a checkout

Notice that neither list can stand alone. The UX decision to show errors at the field is worthless if the error text is light grey on white. The UI decision to use one primary button does not help if the flow has seven steps. That is why we always test the flow in a clickable prototype before the visual design is finished, and then test the finished design again.

Who does what? UX designer, UI designer and product designer

For most small and medium-sized businesses the most effective setup is one designer who covers both UX and UI and sits close to the developers. With us, design and development are under one roof, so the decisions made in Figma survive all the way to the finished code. If you are hiring yourselves, we have written a guide to hiring a UX designer, with questions for the portfolio review and the interview.

What does a UX and UI process look like from start to finish?

Each step has its own deliverable. We cover the difference between wireframes, mockups and prototypes in the guide wireframe vs mockup vs prototype, and how to test with real users in the guide to usability testing.

What do UX and UI design cost?

A freelance UX designer in Denmark typically charges around DKK 600–750 an hour, and agencies typically charge DKK 1,100–1,300 an hour. A small engagement with research, wireframes and visual design of a handful of screens can be done in a few weeks, while a design system for a large product is a project of several months. The biggest saving comes when UX work catches flaws in the flow before any code is written. A change in a wireframe takes minutes, while the same change in a finished product can take days. We break prices down by deliverable in our guide to what UX design costs.

Which misconceptions about UX and UI should you avoid?

• “UX is just a fancier word for design.” UX is a method for making decisions based on how users behave.
• “We know our customers, so we skip research.” Five short interviews almost always reveal something nobody in the company expected.
• “UI is decoration.” Contrast, legibility and clear buttons decide whether people can use the product, and for many they are also a legal requirement.
• “We will do the design at the end.” Once the code is written, the most expensive decisions have already been made.
• “A beautiful Dribbble portfolio means good UX.” Ask for the process behind it: what was tested, and what changed?

Do you need UX, UI or both?

• Users drop off at a specific step, or support keeps getting the same questions: start with UX, for example a UX audit.
• The product works but looks dated and off-brand: start with UI.
• You are building something new from scratch: you need both, in that order.
• You have many screens that all look different: you need a design system.
• You are unsure whether the idea holds: start with research and a prototype.

To learn more about how we work with design, see our page on UX and UI design. And if you have a concrete project, you can get a fixed price within 24 hours, describing exactly which UX and UI deliverables are included.