How to get AI to
translate a document.

What you’ll be able to do

By the end of this you’ll be able to translate a whole file, PDF, Word, PowerPoint, whatever, and get something back that still looks like the original. Same headings. Same tables. Same page count, roughly. And you’ll know how to check it’s actually right, even if you don’t speak a word of the language yourself. That last bit matters more than people think.

Before you start

Right, a few things to get straight before you touch any of this.

Machine translation is genuinely good for everyday stuff. Supplier emails, internal memos, that school letter, a PowerPoint for a client abroad. It is not a certified translation, and it never will be, no matter how good it looks. If you need something for a UK government process, a visa application, a court, anything official like a birth certificate or a degree certificate, you need a human translator who’ll sign a statement confirming it’s a “true and accurate translation of the original document,” with their name and contact details attached. Gov.uk has the details on this (certifying a document). Don’t try to shortcut that one with an app, it won’t hold up.

Second thing: consistency. If your document uses a specific term over and over, a product name, a job title, a legal phrase, decide upfront how you want it translated and write it down. A two-line glossary before you start saves you from a document where “Managing Director” becomes three different things on three different pages. Sounds fussy. Isn’t, really, takes two minutes.

Get set up

There are basically two routes here, and which one you pick depends on what you actually need.

If you want the file back looking like the file, use one of three tools built for that: DeepL, Google Translate, or Microsoft Word if you’ve already got a Microsoft 365 subscription.

DeepL (deepl.com) is my first pick for this, honestly. It handles Word, PowerPoint, Excel, and PDF, including scanned PDFs and images, and it keeps formatting intact. The free version gives you one file a month with a fairly small size cap and a modest text limit. If you need more than that regularly, DeepL Pro raises both limits, check deepl.com/pro for the current details rather than trusting a number I quote here, because these things change.

Google Translate (translate.google.com) is free and does a solid job too. Click “Documents,” then “Browse your computer,” upload your file, and it gives you a “Download translation” button when it’s done. Works with .docx, .pdf, .pptx and .xlsx files up to 10 MB. One catch worth knowing: if your PDF is a scan, or has text sitting inside images, that text will appear in the output file in its original position, but it will not actually be translated. It just carries the image across untouched. Easy to miss if you’re not looking for it.

Microsoft Word, if you’ve got a Microsoft 365 subscription, has this built in. Review, then Translate, then Translate Document. It opens a machine-translated copy in a new window. Needs an internet connection and “connected experiences” switched on in your settings. There’s also Translate Selection if you just want one paragraph done, handy for checking a single clause without translating the whole thing.

Then there’s the other route: using an assistant like ChatGPT, Claude, or Gemini directly. You lose the automatic formatting, they don’t reliably hand back a properly laid-out file, so expect to copy the translated text back into your document yourself. But you gain control. You can give them a glossary. You can tell them the tone you want, formal for a lawyer, plain for a parent. You can ask them to keep headings and numbering exactly as they were. If precision matters more than speed, this is the better route.

Try it yourself

Say you’ve got a Word contract in French and you want it translated with control over terminology. Open ChatGPT, Claude, or Gemini, paste in the text (or upload the file if the tool accepts it), and try something like this:

Translate the following from French to British English, in full, sentence by sentence, do not summarise or shorten. Keep the headings, numbering and paragraph breaks exactly. Use this glossary: siège social = registered office, gérant = manager, société = company. Tone: formal. Text: [paste]

Fill in your own glossary terms, obviously, and paste the actual text where it says “Text:”. You’ll get a full translation back that you then paste into your document, matching the original layout by hand.

If you just want the whole file done fast and don’t need fine control, upload it to DeepL or Google Translate instead, following the click-through steps above. For the school letter, for the supplier invoice, this is usually enough.

One thing worth doing regardless of which route you take: build your glossary before you start, not after. DeepL has a glossary feature built in, though it’s limited on the free tier. For assistants, just put it straight into the prompt as I’ve shown above.

Check the result

This is the part people skip, and it’s the part that actually matters, especially when you can’t read the output yourself.

First, open the translated file next to the original. Same number of pages? Same headings in roughly the same places? Same tables, same structure? If a five-page document came back as three pages, something got dropped or summarised somewhere, and you need to find where.

Second, back-translate. Take a key paragraph, the price, the deadline, the important clause, and run it back through a different tool than the one you used to translate it. DeepL out, Google or an assistant back in, or vice versa. Try this:

Here is an original paragraph and a translation of it. Back-translate the translation into French without looking at the original, then list every place the meaning differs from the original: [original] / [translation]

Any drift in meaning tends to show up clearly once you compare the two versions side by side.

Third, and this catches more errors than anything else: check every number, date, name, and currency symbol by eye. These are the commonest things that go wrong in machine translation, a comma becomes a decimal point, a date format flips, ”£” turns into ”$” somewhere in the process. You can also ask an assistant to do this scan for you:

Check this translated document for numbers, dates, names, currencies and units that differ from the original, and list each mismatch with the page or heading it sits under: [original] / [translation]

And if there’s anyone around who actually speaks the language, even just a colleague, even just for five minutes, ask them to read the bits that matter most. The price. The deadline. The one clause that could get you in trouble if it’s wrong. You don’t need them to read the whole thing.

If it doesn’t work

Layout completely broken, text overlapping, tables collapsed? Nine times out of ten this means your PDF had text sitting inside images, or it was a scanned document where the “text” was never actually text, just a picture of text. You’ll need to run it through OCR first, or retype the parts that actually matter by hand.

Terms flipping between different words for the same thing, “company” one paragraph, “organisation” the next, when the original used one consistent term? Your glossary either wasn’t specific enough or wasn’t used. Add it (or add to it) and translate again.

File too big for the free tier? Split it by chapter or section and run each part through separately. Bit more admin, but it works.

Assistant gave you a summary instead of a full translation? This happens more than you’d think, they sometimes decide to be “helpful” and condense things. Tell it plainly: “translate in full, sentence by sentence, do not shorten.” Usually fixes it straight away.

Now, privacy. This is the bit not to skip. The free version of DeepL processes what you upload to improve its own systems, that’s stated in DeepL’s own privacy policy, it’s not a secret, but it’s easy to miss. Don’t upload contracts, medical letters, payslips, or anything containing someone else’s personal data to a free tool. DeepL Pro is different: it states it does not use your content for training and deletes it after translation. If you’re dealing with anything confidential, check your employer’s rules before it goes anywhere near any of these tools, free or paid. And if you’re pasting text into an assistant rather than uploading a file, strip out names and account numbers first if you can. Takes a moment, saves a headache.

Questions people ask

Can AI give me a certified translation for a visa or court?

No. Machine translation is not a certified translation, no matter how good it looks. For a UK government process, a court, a birth certificate or a degree certificate, you need a human translator who'll sign a statement confirming it's a "true and accurate translation of the original document", with their name and contact details attached.

Which tool should I use to translate a document and keep the layout?

Use one of three tools built for that: DeepL, Google Translate, or Microsoft Word if you already have a Microsoft 365 subscription. DeepL handles Word, PowerPoint, Excel and PDF, including scanned PDFs and images, and keeps formatting intact.

Is document translation free, and what costs money?

Google Translate is free and works with .docx, .pdf, .pptx and .xlsx files up to 10 MB. DeepL's free version gives you one file a month with a fairly small size cap and a modest text limit; DeepL Pro raises both, and Word's built-in translation needs a Microsoft 365 subscription.

Is it safe to upload a contract or payslip to a translation tool?

Don't upload contracts, medical letters, payslips, or anything containing someone else's personal data to a free tool, as the free version of DeepL processes uploads to improve its own systems. DeepL Pro states it does not use your content for training and deletes it after translation. Check your employer's rules for anything confidential.

How do I check a translation if I don't speak the language?

Open the translated file next to the original and compare page count, headings and tables. Then back-translate a key paragraph using a different tool than the one you translated with, and check every number, date, name and currency symbol by eye. If anyone around speaks the language, ask them to read the bits that matter most.

Keep exploring

If you found this useful, there’s more on the site worth a look. “How to get AI to translate a live conversation” covers the real-time version of this, useful for calls or meetings. “How to get AI to summarise a document” is the opposite job to this one, condensing rather than converting. And “How to get AI to read a PDF” is worth reading first if your file is a scan or has awkward formatting before you even get to translation.

Sources and review notes

https://www.deepl.com/en/features/document-translation https://www.deepl.com/en/pro https://www.deepl.com/en/privacy https://support.google.com/translate/answer/2534559?hl=en https://support.microsoft.com/en-us/office/languages/translate-text-into-a-different-language https://www.gov.uk/certifying-a-document

Review date: 2026-09-22