All Caps vs Bold

Question

Often, I am given text to put on our website. Often, they'll use all caps for emphasis. I often wonder if it's inappropriate and if there's a strong case for using bold instead. Some examples

Check out our NEW order page

All orders MUST BE PLACED by June 10th

Order today and SAVE BIG

When is it appropriate or inappropriate to use all caps?

Answer 1

In depends on how you're using the text.

You can increase and decrease visibility of text by applying different styles to your text. Let's focus on things you can do to increase visibility of text, since that's what your question is about.

When to use all bold or WHEN TO USE ALL CAPS

Use ALL CAPS or bold to put emphasis on text you want to get your users' attention to.

You can increase text visibility for text you want your users to see first by making it either stand out in size (UPPERCASE) or visual weight (Bold). Just look at how the two examples from the previous sentence stand out.

Let's take the examples you give in your question;

Order today and SAVE BIG

'SAVE BIG' stands out. You can use that to put attention on 'SAVE BIG'. I can imagine that's what you want when you design something for retail/sales. Only use all caps for small strings you want to put emphasis on.

There's a great article about text visibility here. Check out number 5.

When not to use all caps

Do not make long body text all caps or bold.

At body text sizes, cap­i­tal let­ters—or sim­ply caps—are harder to read than nor­mal low­er­case text. Why? We read more low­er­case text, so as a mat­ter of habit, low­er­case is more fa­mil­iar and thus more leg­i­ble. Fur­ther­more, cog­ni­tive re­search has sug­gested that the shapes of low­er­case let­ters—some tall (dhkl), some short (aens), some de­scend­ing (gypq)—cre­ate a var­ied vi­sual con­tour that helps our brain rec­og­nize words. Cap­i­tal­iza­tion ho­mog­e­nizes these shapes, leav­ing a rec­tan­gu­lar contour.

Source: All caps

Also do not make labels bold or all caps.

However, bold labels resulted in an almost sixty-percent increase in saccade time to move from the label to the input field—from 50ms without bold labels to 80ms with bold labels—with no apparent advantage from the more prominent labeling. Bold labels were more difficult for users to read and perceive—probably because there was more visual confusion between the bold text and the heavy adjacent borders of the input fields.

Source: Label Placement in Forms

Final note

Don't forget to look at your corporate identity/style. Is a bold font or all caps part of your branding?