Mobile usability problems your desktop will never show you

Aug 29
3 min read

Updated: 3 days ago

Introduction

The site was checked on a laptop, approved on a laptop, and is updated on a laptop. It looks correct, the layout holds together, and everybody involved is satisfied with it.

The majority of visitors are on a phone, holding it in one hand, often outdoors, frequently distracted. What they encounter is a menu that will not close, a form field that pushes the keyboard over the button, and a telephone number that is an image rather than something they can tap. None of this is visible from the machine where the decisions are made.

1. Mobile usability problems are invisible from a desktop

Change where you test.

Open your own site on a real phone, not a resized browser window, and try to complete the thing you want visitors to do. Ten minutes of that produces a longer and more accurate list than any automated report.

2. Check that tap targets are big enough and far enough apart

The most common physical failure.

Links crowded into a row, small icons and closely stacked menu items are all difficult to hit with a thumb. Adequate size and adequate spacing between them fixes a category of frustration that otherwise reads to the visitor as a broken site.

3. Make sure nothing scrolls sideways

A signal of a deeper layout problem.

If the page can be dragged horizontally, something is wider than the screen — usually a table, an image or an embedded element. It looks careless, and it often means content is cut off entirely at the edge.

4. Test the forms with the keyboard open

Where enquiries are quietly lost.

On a phone the keyboard covers half the screen, and a submit button can end up underneath it. Check that every field is reachable, that the right keyboard appears for numbers and email addresses, and that the button is visible when the last field is filled.

5. Make contact details tappable

An easy win that is missed constantly.

A telephone number should dial when tapped, an address should open a map, and an email address should open a mail application. Numbers set as images or as plain unlinked text force people to copy them by hand, and many will not bother.

6. Look at the menu on a small screen

Navigation degrades badly at this width.

Check that the menu opens, closes, does not obscure the page, and shows the pages that matter. Deep nested menus that work with a mouse become unusable with a thumb, and the important pages disappear two levels down.

7. Check text size and contrast outdoors

Conditions, not just design.

Small grey text on a white background is legible in an office and unreadable in daylight. Take a phone outside and look at your own site, particularly any text sitting on top of a photograph.

8. Watch what popups do on a small screen

The most damaging single element.

An overlay that covers a desktop page partially can cover a phone screen entirely, sometimes with a close button off the edge. Anything appearing on arrival should be tested on a phone before it is allowed to run.

9. Test on more than one device

One phone is not a sample.

Behaviour differs across screen sizes, operating systems and browsers, and an older or smaller device will surface problems a current flagship hides. Two or three genuinely different handsets catch nearly everything worth catching.

Ask somebody outside the business to complete a task on their own phone while you watch without helping. The points where they hesitate are the real list, and it is usually shorter and more specific than anything produced by discussion.

Conclusion

Test on an actual phone rather than a narrowed desktop window, because the differences that matter do not reproduce.

Give tap targets enough size and spacing for a thumb, eliminate horizontal scrolling because it means something is overflowing the screen, test forms with the keyboard open so the submit button is not hidden, make telephone numbers and addresses tappable, check the menu opens and shows the pages that matter, read your own text outdoors, test any popup on a small screen before allowing it to run, use more than one device, and watch somebody unfamiliar attempt the task.