A complete guide to word-wrap, overflow-wrap, and word-break in CSS

Making a site responsive so that it displays correctly on all devices is very important in this day and age. Unfortunately, despite your best efforts to do so, you may still end up with broken layouts.

Broken layouts sometimes happen because certain words are too long to fit in their container. Content overflow can occur when you are dealing with user-generated content you have no control over, such as the comments section of a blog post. Therefore, you need to apply styling to prevent content from overflowing their container.

Using word-wrap, overflow-wrap, and word-break CSS properties

You can use the word-wrap, overflow-wrap, or word-break CSS properties to wrap or break words that would otherwise overflow their container. This article is an in-depth tutorial on the word-wrap, overflow-wrap, and word-break CSS properties and how you can use them to prevent content overflow from ruining your nicely styled layout.

Before we get started, let us understand how browsers wrap content in the next section.

How does content wrapping occur in browsers?

Browsers and other user agents perform content wrapping at allowed breakpoints, referred to as “soft wrap” opportunities. A browser will wrap content at a soft wrap opportunity, if one exists, to minimize content overflow.

In English and most similar writing systems, soft wrap opportunities occur by default at word boundaries in the absence of hyphenation. Because words are bound by spaces and punctuation, that is where soft wraps occur.

Though soft wraps occur in space characters in English texts, the situation might be different for non-English writing systems. Some languages do not use spaces to separate words, meaning that content wrapping depends on the language or writing system. The value of the lang attribute you specify on the html element is mostly used to determine which language system is in use.

This article will focus mainly on the English language writing system. The default wrapping at soft wrap opportunities may not be sufficient if you are dealing with long, continuous text, such as URLs or user-generated content, which you have very little or no control over.

Before we go into a detailed explanation of these CSS properties, let us look at the differences between soft wrap break and forced line break in the section below.

What is the difference between a soft wrap break and a force line break?

Any text wrap that occurs at a soft wrap opportunity is referred to as a soft wrap break. For wrapping to occur at a soft wrap opportunity, you need to make sure you’ve enabled wrapping. For example, setting the value of white-space CSS property to nowrap will disable wrapping.

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Force line breaks are caused by explicit line-breaking controls or line breaks marking the end or start of blocks of text.

Word-wrap and overflow-wrap CSS properties

The name word-wrap is the legacy name for the overflow-wrap CSS property. Word-wrap was originally a non-prefixed Microsoft extension. It was not part of the CSS standard, though most browsers implemented it with the name word-wrap. According to the draft CSS3 specification, browsers should treat word-wrap as a legacy name alias of the overflow-wrap property for compatibility.

Most recent versions of popular web browsers have implemented the overflow-wrap property.

Below is what the draft CSS3 specification says about the overflow-wrap property:

This property specifies whether the browser may break at otherwise disallowed points within a line to prevent overflow when an otherwise-unbreakable string is too long to fit within the line box.

If you have a white-space property on an element, you need to set its value to allow wrapping for overflow-wrap to have an effect.

Below are the values of the overflow-wrap property. You can also use the global values inherit, initial, revert, and unset with overflow-wrap, but we won’t cover them here.

overflow-wrap: normal;
overflow-wrap: anywhere;
overflow-wrap: break-word;

In the subsections below, we will look at the values of the overflow-wrap CSS property outlined above to understand the behavior of this property.

Normal in CSS

Applying the value normal will make the browser use the default line-breaking behavior of the system. For English and other related writing systems, line breaks will therefore occur at white spaces and hyphens.

.my-element{
    overflow-wrap: normal;
}

In the image below, there is a word in the text that is longer than its container. Because there is no soft wrap opportunity in it, and the value of the overflow-wrap property is normal, the word overflows its container. It describes the default line-breaking behavior of the system.

Anywhere

Using the value anywhere will break an otherwise unbreakable string at arbitrary points between two characters. It will not insert a hyphen character even if you apply the hyphens property on the same element.

The browser will break the word only if displaying the word on its line will cause an overflow. If the word still overflows when placed on its line, it will break the word at the point where an overflow would otherwise occur.

When you use anywhere, the browser will consider the soft wrap opportunities introduced by the word break when calculating min-content intrinsic sizes:

.my-element{
   overflow-wrap: anywhere;
}

Unlike in the previous section, where we used overflow-wrap: normal, in the image below, we are using overflow-wrap: anywhere. The overflowing word that is otherwise unbreakable is broken into chunks of text using overflow-wrap: anywhere so that it fits in its container.

It’s important to note that anywhere is not yet supported by some browsers. The image below shows the browser support according to caniuse.com. Don’t use overflow-wrap: anywhere in production if you intend to have higher browser support.

Break-word

The value break-word is like anywhere in terms of functionality. If the browser can wrap the overflowing word to its line without overflowing, that is what it will do.

However, if the word still overflows its container even when it is on its line, the browser will break it at the point where the overflow would otherwise occur:

.my-element{
   overflow-wrap: break-word;
}

The image below shows how the browser breaks the overflowing text in the previous section when you apply overflow-wrap: break-word. Notice that the image below appears the same as the image in the last subsection. The difference between overflow-wrap: anywhere and overflow-wrap: break-word is in the calculation of min-content intrinsic sizes.

The difference between anywhere and break-word is apparent when calculating the min-content intrinsic sizes. With break-word, the browser doesn’t consider the soft wrap opportunities introduced by the word break when calculating min-content intrinsic sizes, but it does with anywhere. For more about min-content intrinsic sizes, you can read this article.

The value break-word has decent coverage among the most recent versions of desktop browsers. Unfortunately, you cannot say the same about their mobile counterpart. It is, therefore, safer to use the legacy word-wrap: break-word instead of the more recent overflow-wrap: break-word.

The image below shows browser support for overflow-wrap: break-word according to caniuse.com. The most recent versions of desktop browsers have support while support for some mobile browsers is unknown.

Word-break CSS property

Word-break is another CSS property you can use to specify soft wrap opportunities between characters. You can use this property to break a word at the exact spot where an overflow would occur and wrap it onto the following line.

Below is what the draft CSS3 specification says about the word-break CSS property:

This property specifies soft wrap opportunities between letters, i.e., where it is “normal” and permissible to break lines of text. It controls what types of letters the browser can glom together to form unbreakable “words” — causing CJK characters to behave like non-CJK text or vice versa.

Below are the possible values of the word-break CSS property. Like overflow-wrap, you can also use the global values inherit, initial, revert, and unset with word-break, but we won’t cover them here:

word-break: normal;
word-break: break-all;
word-break: keep-all;

Break-word is also a value of the word-break CSS property, though it is deprecated. However, browsers still support it for legacy reasons. Specifying this property has the same effect as word-break: normal and overflow-wrap: anywhere.

Now that we know the break-word CSS property and its corresponding values, let us look at them in the subsections below.

Setting word-break to Normal

Setting the value of the word-break property to normal will apply the default word breaking rules:

.my-element{
   word-break: normal;
}

The image below illustrates what happens when you apply the styling word-break: normal to a block of text that contains a word longer than its container. What you see is the browser’s usual word-breaking rules in effect.

Break-all

The value break-all will insert a line break at the exact point where the text would otherwise overflow for non-Chinese, non-Japanese, and non-Korean writing systems.

It will not put the word on its own line, even if doing so will prevent the need to insert a line break:

.my-element{
   word-break: break-all;
}

In the image below, I applied word-break: break-all styling to a p element of width 240px containing an overflowing text. The browser inserted a line break at the point where an overflow would occur and wrapped the remaining text to the following line.

Using break-all will break a word between two characters at the exact point where an overflow would occur in English and other related language systems. However, it won’t apply the same behavior to Chinese, Japanese, and Korean (CJK) texts.

It doesn’t apply the same behavior for CJK texts because CJK writing systems have their own rules for applying breakpoints. Creating a line break between two characters arbitrarily just for the sake of avoiding overflow might significantly change the overall meaning of the text. For CJK systems, the browser will apply line breaks at the point where such breaks are allowed.

Keep-all

If you use the value keep-all, the browser will not apply word breaks to CJK texts even if there is content overflow. The effect of applying keep-all value is the same as that of normal for non-CJK writing systems:

.my-element{
   word-break: keep-all;
}

In the image below, applying word-break: keep-all has the same effect as word-break: normal because I am using a non-CJK writing system (English).

The image below shows the browser support for word-break: keep-all according to caniuse.com. This value has support in most popular desktop browsers. Unfortunately, it is not the case for mobile browsers.

Now that we have looked at the overflow-wrap and word-break CSS properties, what is the difference between the two? The section below will shed light on that.

What is the difference between overflow-wrap and word-break?

You can use the CSS properties overflow-wrap and word-break to manage content overflow. However, there are differences in the way the two properties handle it.

Using overflow-wrap will wrap the entire overflowing word to its line if it can fit in a single line without overflowing its container. The browser will break the word only if it cannot place it on a new line without overflowing. In most cases, the overflow-wrap property or its legacy name word-wrap might manage content overflow.

The overflow-wrap property is relatively new therefore has limited browser support. You can use the legacy name word-wrap instead if you want higher browser support. Using word-wrap: break-word will wrap the overflowing word onto a new line and goes ahead to break it between two characters if it still overflows its container.

Word-break will ruthlessly break the overflowing word between two characters even if placing it on its line will negate the need for word break. Some writing systems, like the CJK writing systems, have strict word breaking rules the browser takes into consideration when creating line breaks using word-break.

Troubleshooting CSS content overflow with Chrome DevTools

More often than not, you might need to fix broken layouts caused by content overflow, as complex user interfaces are now commonplace in front-end development. Modern web browsers come with tools for troubleshooting such layout issues, such as Chrome DevTools.

It provides the capability to select an element in the DOM tree so that you can view, add, and remove CSS declarations and much more. It will help you track down the offending CSS style in your layout and fix it with ease.

To open the Chrome DevTools, you can use F12. When open, it looks like in the image below. Selecting an element in the DOM tree will display its corresponding CSS styles. You can modify the styles and see the effect on your layout as you track down the source of the bug.

As already mentioned, if you have white-space property on an element, set its value to allow wrapping for overflow-wrap: anywhere or overflow-wrap: break-word to work.

Setting the value of overflow-wrap property to anywhere or break-word on a table content won’t break an overflowing word like in the examples above. The table will overflow its container and create a horizontal scroll if necessary.

To get the table to fit within its container and overflow-wrap to work, set the value of the table-layout property to fixed and set the table width to 100% or to some fixed value.

Conclusion

As pointed out in the above sections, overflow-wrap and word-break are similar in so many ways. You can use both of them for line-breaking controls.

The name overflow-wrap is an alias of the legacy word-wrap property. Therefore, you can use the two interchangeably. However, it is worth mentioning that the browser support for the newer overflow-wrap property is still low. You are better off using word-wrap instead of overflow-wrap if you want near-universal browser support. According to the draft CSS3 specification, browsers and user agents should continue supporting word-wrap for legacy reasons.

If you are looking to manage content overflow, overflow-wrap or its legacy name word-wrap might be sufficient.

You can also use word-break to break a word between two characters if the word overflows its container. Just like overflow-wrap, you need to tread with caution when using word-break because of limitations in the browser support.

Now that you know the behavior associated with the two properties, you can decide where and when to use them. Did I miss anything? Leave a comment in the comments section. I will be happy to update this article.

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