A responsive website should work properly whether someone visits it on a phone, tablet, laptop or large desktop screen.
That sounds simple, but responsive design problems are not always obvious. A page might look fine on your own phone while the navigation overlaps on a slightly wider device, a form becomes difficult to use in landscape mode, or an image pushes the page beyond the edge of the screen.
Testing responsive design properly means checking how your website behaves across a range of screen sizes, not just opening it on one phone and assuming everything works.
This guide explains how to test responsive design on your WordPress website, what to look for and how to identify problems before they affect visitors.
What Does Responsive Design Testing Check?
Responsive design allows a website layout to adapt as the available screen space changes.
Depending on the width of the browser, this might mean:
- Columns stacking vertically
- Navigation changing into a mobile menu
- Images resizing
- Text wrapping differently
- Buttons moving or expanding
- Sidebars appearing below the main content
- Grids changing from four columns to two or one
- Spacing becoming tighter on smaller screens
Responsive testing checks that these changes happen correctly and that the site remains easy to read and use.
You are not simply checking whether the website technically fits on a smaller screen. You also need to consider whether visitors can comfortably navigate, read content, complete forms and interact with important features.
Start by Resizing Your Browser
One of the quickest ways to spot responsive problems is simply to resize your browser window.
Open a page on your desktop computer and slowly make the browser narrower.
Watch what happens as the available space decreases.
A responsive layout should normally adjust gradually or at defined breakpoints. You might see columns stack, navigation change format or images reduce in size.
Look for problems such as:
- Text overlapping other elements
- Horizontal scrolling
- Images extending outside their containers
- Buttons disappearing off screen
- Navigation wrapping awkwardly
- Large gaps appearing between sections
- Columns becoming too narrow
- Headings breaking across too many lines
Do not test only at a few neat screen widths. Slowly resizing the browser can reveal problems at awkward intermediate widths that predefined device sizes may miss.
This is a useful first check, but browser resizing alone is not enough.
Use Your Browser’s Responsive Testing Tools
Modern browsers include tools specifically for testing responsive layouts.
In Google Chrome, you can open Chrome DevTools and enable the Device Toolbar. Firefox has a similar Responsive Design Mode.
These tools allow you to change the viewport size without physically resizing the entire browser window.
You can test common phone and tablet dimensions, rotate between portrait and landscape views, or enter your own width and height.
The most useful option is often the general responsive mode rather than relying entirely on named device presets.
A website should not work only at the exact dimensions of a particular iPhone or Android device. It should respond properly throughout the range of possible screen widths.
Try gradually changing the width and watch for the point where each part of the layout changes.
If something breaks at 760 pixels wide but works at 768 pixels, for example, you have found a responsive issue even if none of the device presets happen to use that exact width.
Test on Real Devices Too
Browser tools are extremely useful, but they are still simulations.
You should test important pages on real devices where possible.
A real phone or tablet can reveal issues that are difficult to reproduce accurately on a desktop computer, including:
- Touch controls
- On-screen keyboards
- Mobile browser menus
- Sticky headers
- Fixed buttons
- Form fields
- Font rendering
- Scrolling behaviour
- Pop-ups
- Cookie notices
- Screen rotation
You do not need to own every device on the market.
Testing on a recent phone and tablet alongside desktop browser testing will catch many common problems. If your website receives significant traffic from a particular device or browser, include that in your testing as well.
Test More Than Just Mobile and Desktop
It is easy to think of responsive design as having only two states: desktop and mobile.
In reality, visitors use a much wider range of screen sizes.
A useful testing range includes:
- Narrow mobile screens
- Larger smartphones
- Portrait tablets
- Landscape tablets
- Smaller laptops
- Standard desktop screens
- Wide desktop displays
Intermediate widths are particularly important.
Many responsive problems appear between the main breakpoints rather than at the smallest or largest screen size.
For example, a navigation menu might fit comfortably at 1200 pixels and switch to a mobile menu at 800 pixels, but become cramped at 900 pixels.
Testing continuously across different widths helps you find these gaps.
Check the Header and Navigation
The header is one of the first areas you should test.
It often contains several elements competing for limited space, including:
- Logo
- Main navigation
- Dropdown menus
- Search
- Telephone numbers
- Account links
- Shopping basket
- Call-to-action buttons
On smaller screens, the navigation will normally collapse into a mobile menu.
Check that the menu opens and closes correctly and that every menu item remains accessible.
If there are dropdown menus, test those as well. Hover behaviour that works on a desktop does not necessarily translate well to a touchscreen.
Also check sticky headers carefully. A header that occupies a reasonable amount of space on desktop can cover a large part of a mobile screen if it does not adapt properly.
Check Text and Content
Content needs to remain readable across every screen size.
Look at paragraphs, headings, lists and other text elements.
Check that:
- Font sizes remain comfortable to read
- Headings do not become excessively large
- Long words or URLs do not force the page wider
- Lines are not uncomfortably long on large screens
- Text does not become squeezed into narrow columns
- Content does not overlap images or buttons
- Spacing remains consistent
Pay particular attention to large headings.
A heading that looks good on desktop can easily wrap into four or five lines on a phone if the font size does not adjust.
Test Images and Other Media
Images should normally scale within the width of their container.
Check that images do not cause horizontal scrolling or extend beyond the page.
You should also check what happens to important parts of an image when it is cropped.
Large banners and hero images can look completely different on a narrow screen. If text, faces or products sit close to the edge of the original image, they may disappear when the image is cropped for mobile.
Test other media as well, including:
- Videos
- Maps
- Embedded social posts
- Iframes
- Galleries
- Sliders
Embedded content is a common source of responsive problems because it may have fixed dimensions that do not adapt automatically.
Check Forms and Interactive Elements
A website can look responsive while still being difficult to use.
Forms are a good example.
Check contact forms, enquiry forms, login screens, newsletter forms and checkout forms on smaller screens.
Make sure:
- Fields fit within the viewport
- Labels remain visible
- Buttons are easy to tap
- Validation messages are readable
- Dropdown menus work correctly
- Date pickers fit on screen
- The mobile keyboard does not hide important controls
- Multi-column forms stack appropriately
Buttons and links should also be large enough to use comfortably on a touchscreen.
Two small links positioned very close together may be easy to click with a mouse but frustrating to tap with a finger.
Test Pop-Ups, Banners and Fixed Elements
Anything positioned above the main page content deserves extra attention.
This includes:
- Cookie banners
- Live chat buttons
- Promotional pop-ups
- Sticky call-to-action bars
- Notification banners
- Floating social buttons
These elements can overlap each other or cover important content on smaller screens.
Check both portrait and landscape views.
Landscape mode can be especially revealing because the available vertical space becomes much smaller.
A large cookie banner combined with a sticky header can leave very little room for the actual website.
Check Tables and Complex Layouts
Tables, pricing comparisons and other wide layouts can be difficult to display on mobile devices.
If your website contains tables, check what happens when the screen becomes narrower than the table.
Depending on the content, a good responsive approach might:
- Allow horizontal scrolling within the table
- Stack information vertically
- Simplify the number of columns
- Change the layout entirely on smaller screens
The correct solution depends on what the visitor needs to understand.
The same applies to card layouts and grids.
A row of four cards might become two columns on a tablet and one column on a phone.
Check that cards remain in the correct order and that buttons, images and text remain aligned.
Check WooCommerce Pages
If you run a WooCommerce website, responsive testing should include more than the homepage.
Test important shopping pages such as:
- Shop archives
- Product pages
- Product galleries
- Variation selectors
- Basket
- Checkout
- Account pages
The checkout deserves particular attention.
Customers should be able to enter their details, select payment options and complete their purchase without zooming, horizontal scrolling or controls being hidden off screen.
A responsive issue during checkout can directly affect sales.
Test Portrait and Landscape Orientation
Phones and tablets can be rotated, so check your website in both portrait and landscape.
A layout that works well in portrait can behave differently when the viewport suddenly becomes wider and shorter.
Watch for:
- Navigation changes
- Sticky elements
- Full-screen sections
- Pop-ups
- Video players
- Forms
- Content using viewport height
Landscape testing is especially useful for identifying elements that take up too much vertical space.
Test More Than One Page
Do not test only the homepage.
WordPress websites usually contain several templates, and they may behave differently.
Check representative examples of:
- Homepage
- Standard page
- Blog post
- Blog archive
- Search results
- Contact page
- Landing pages
- Forms
- Custom post types
- WooCommerce pages if applicable
A responsive problem may exist only within one template or one particular component.
For example, your homepage could work perfectly while blog posts contain an old fixed-width image that causes horizontal scrolling.
Common Responsive Design Problems
Some issues appear repeatedly when testing WordPress websites.
Horizontal Scrolling
If you can move the entire page sideways on mobile, something is probably wider than the viewport.
This might be an image, table, iframe, long URL, custom layout or fixed-width element.
Overlapping Content
Text, images or buttons may begin to overlap when there is no longer enough space for the original layout.
This often indicates that an element has been given a fixed width or position.
Broken Mobile Menus
Check that the mobile menu button appears at the right time and that the menu itself opens properly.
Also check dropdowns, submenus and close buttons.
Oversized Headings
Large desktop typography can dominate the screen on mobile.
Responsive font sizing can help maintain a sensible visual hierarchy.
Fixed-Width Images or Embeds
Older content may contain images, videos or iframes with dimensions that do not adapt to smaller screens.
These can push the entire layout wider than the viewport.
Buttons That Are Difficult to Tap
Small controls can be frustrating on touchscreen devices.
Allow enough space around important buttons and links so visitors can select them accurately.
Pop-Ups Covering the Screen
A desktop pop-up may become almost impossible to close when displayed on a phone.
Always test overlays at narrow widths.
What Should You Do If You Find a Problem?
First, reproduce the problem consistently.
Make a note of:
- The page
- The approximate screen width
- The browser
- What should happen
- What actually happens
Then identify the element causing the issue.
The problem might come from:
- Your WordPress theme
- A page builder
- A plugin
- Custom CSS
- Custom HTML
- An embedded third-party service
- Old content created before the current theme
Avoid making random CSS changes until you understand the cause.
A quick adjustment at one screen width can accidentally create a new problem somewhere else.
If the issue requires changes to your theme, it is also worth following a safe process rather than editing production code without a backup. Our guide to customising your WordPress theme explains the options in more detail.
If the problems are widespread because of the theme itself, you may also want to review our guide to choosing the right WordPress theme.
Responsive Design Testing Checklist
Before considering your testing complete, check:
- The layout at narrow, medium and wide screen sizes
- Intermediate widths between major breakpoints
- Portrait and landscape orientation
- Header and navigation
- Dropdown menus
- Headings and paragraph text
- Images and videos
- Forms
- Buttons and links
- Tables and grids
- Pop-ups and cookie banners
- Sticky and fixed elements
- Key WordPress templates
- WooCommerce pages where relevant
- At least one real mobile device
You do not need to make every screen size look identical.
Responsive design is about ensuring the website adapts appropriately while remaining usable and visually consistent.
Keep Responsive Testing Part of Website Maintenance
Responsive design testing should not be something you do only when a website is first launched.
Theme updates, plugin changes, new page layouts and custom CSS can all introduce problems later.
A quick responsive check after significant design changes can prevent small layout issues from remaining unnoticed for months.
If you have found responsive problems on your WordPress website and would prefer us to investigate them for you, our one-off WordPress support can help diagnose and fix layout, theme and mobile display issues.
