What is text expansion and why does it matter?

Some languages require more space than others to express the same thing. When translating from English into French, the French result might require 30% more space than the English source, because the French language uses more words. Other language pairs contract. For example, Korean script is more compact than other languages. When translating from English into Korean, the Korean target will take up 10-15% less space on the page. Finally, some expansion rates are hard to predict. Depending on the subject matter and the writing style or tone, a Japanese translation could end up using up to 60% more or 10% fewer characters than the English source.Designing your products, content, and software to accommodate text expansion saves time and money during localization.

Software Localization

Our project managers almost always encounter problems with text expansion during software localization projects. If the developer did not provide sufficient space for text expansion, translating the user interface for an application becomes very challenging.  A field that accommodates user interface strings in one language might be too small for its translation. When developing an application, follow best practices for internationalization to facilitate localization for different languages and markets later.

Layout and design

A website, brochure, or advertisement that looks perfect in English might look sparse in Chinese. Or it might look crowded in Russian. These types of media require multilingual desktop publishing services to adjust the design to suit the text after the translation has been completed. Images and design elements for specific foreign markets also require reformatting.

If the original English-language design includes insufficient white space, the DTP team might reduce font size and reduce spacing between words. Online readers can zoom in a bit (though one should not impose on the user, even momentarily). However, for printed content, smaller fonts won’t work. The DTP team may need to add new pages, reflow the text, and rearrange images. This will increase your costs and turnaround time. Prevent these problems by designing for localization.


Keep the principle of text expansion in mind when planning for voiceovers. Again, some languages simply require more words than others. Text expansion can cause problems with timing.

For example, when translating an English-language informational video into Portuguese, the text expands. If the original English narration proceeds quickly, recording the Portuguese voice-over to match the pace of the original might require speed-reading from the voice actor.  Or, the video editor will need to alter the visuals to accommodate the narration.

When producing a video intended for localization, take a leisurely pace with the English source. If you need localization of an existing video, the translation team should understand the principles of scriptwriting. A skilled translator can condense and paraphrase to accommodate your needs. You might also adapt the video to match the voice-over by slowing it down or freezing certain frames if you can.

How can you predict text expansion?

Click to enlarge this chart of average expansion (or contraction) rates. Rates appear as either a positive number (expansion) or negative number (contraction).

To more precisely predict expansion on a print or digital project, we run a pseudo-translation on the source content. We upload the source text into a tool that generates a fake translation that mimics the qualities of the target language and predicts the expansion of the target text. Pseudo-translation helps us anticipate and prepare for design changes or the need to use abbreviations.

It’s never too early to start planning for localization. If you design your products, marketing content, and software with text expansion in mind, you can prevent headaches later. Your language service partner can help you manage these and other design challenges of translation and localization.