Content4 min read
Text Expansion in Translation: How Much Longer Your Caption Gets
Every published expansion table gives one percentage per language. The number that decides whether your caption fits is not that one - it is how short the English was to begin with.
Text expansion in translation is the amount a string grows when it moves into another language. German and French run longer than English, Chinese and Japanese run shorter, and the single most useful fact about it is the one usually left out: the shorter the source, the bigger the expansion. A caption is made of short strings, which is why a flat percentage per language predicts it badly.
Why a short string expands more
A grammar has fixed costs. Articles, prepositions, case endings, politeness markers — a language that needs them needs them whether the sentence is five words or fifty.
On a fifty-word sentence those costs are spread thin and the total lands a modest percentage above the English. On a three-word button label there is nothing to spread them over, and the same grammar can double the string. This is not a quirk of any one language; it is arithmetic, and the W3C documents the same effect for interface strings in its note on text size in translation, where the recommended allowance falls as the source string gets longer.
For social copy this matters more than it does for software, because the two things you translate most — a title and the first line of a caption — are exactly the short strings at the extreme end of the curve.
Rough expansion, by source length
These are planning ranges rather than measurements. A skilled translator can write shorter than any of them; the point of a range is to leave the room before anybody has to ask for it.
| Language | A short label | A caption-length sentence | A paragraph |
|---|---|---|---|
| German | up to ×2 | +35% | +20% |
| French | up to ×1.9 | +25% | +18% |
| Spanish | up to ×1.85 | +25% | +20% |
| Portuguese (BR) | up to ×1.85 | +25% | +20% |
| Polish | up to ×1.9 | +28% | +22% |
| Russian | up to ×1.8 | +22% | +15% |
| Turkish | up to ×1.6 | +12% | +5% |
| Japanese | ×0.9 | −35% | −40% |
| Chinese (Simplified) | ×0.8 | −45% | −50% |
| Korean | ×1.0 | −20% | −25% |
Two of those rows deserve a caveat rather than a number.
Turkish barely expands in characters because it is agglutinative — a whole English phrase becomes one long Turkish word. The character count hardly moves and the longest single word doubles, which breaks a narrow column even though the budget says it fits.
Japanese and Chinese get shorter in characters and take about the same room on screen, because the characters are twice as wide. On X they also cost twice as much against the limit, which is covered in Japanese character count on X.
What text expansion actually costs you
Three different things, and only the first is obvious.
The caption is over the limit. Recoverable, annoying, and someone has to decide what to cut.
The hook is now below the fold. Worse, and silent. An English opening of 115 characters is inside Instagram's fold; the German at 150 is not, and nothing warns you. The reader never opens the caption, so there is no truncation to notice. The first line of a caption is the sentence this happens to.
Text baked into an image no longer fits. The most expensive of the three, because it means re-exporting the asset rather than editing a field. This is why text on a carousel slide should be budgeted with expansion in mind if the deck is ever going out in another language.
FreeMentioned in this article
Translation Length BudgetIt fits in English. The question is whether it fits in German.It picks the multiplier from the length of what you pasted rather than applying one flat figure, checks the projection against the network's real limit, and reports the longest English source that still fits in every language you selected.
How to budget for it
- Pick the tightest surface and the longest language you actually publish to.
- Divide the limit by that expansion. A 280-character limit and a 1.35 multiplier is a
207-character English caption.
- Write the English to that number, not to the English limit.
- Keep the first line shorter than you think. The fold is a harder constraint than the limit
and it moves the same way.
- Check the count with the platform's own rule, not with a character counter that assumes
every character costs one. The social media character counter applies each network's own counting.
How much longer is German than English?
It depends on the length of the source. A short label can be twice as long; a caption-length sentence typically lands around 35% longer, and a full paragraph nearer 20%.
Why do short strings expand more in translation?
Because a grammar's fixed costs - articles, prepositions, endings - are the same whether the sentence is short or long. On a long sentence they are spread thin; on a three-word label there is nothing to spread them over.
Does Japanese text get shorter?
In characters, yes - often 30-40% shorter. On screen it takes about the same room, because the characters are twice as wide, and on X it costs twice as much against the limit.
Are text expansion percentages accurate?
They are planning ranges, not measurements of any particular translation. Use them to leave room in the source; do not use them to predict a specific result.
Paste the English into the translation length budget and write to the number it gives you.
Put it to work
Tools for the job you just read about
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Translation Length Budget
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Weighted Character Counter
Why your editor says 240 and the post box says 287.
Count →1 runs
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Carousel Copy Splitter
A list, split into slides the words will actually fit on.
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