How to Use AI to Translate a Document (and Get It Right)

A supplier sends you a 12-page agreement in German. A client in Madrid wants your onboarding guide in Spanish by Friday. You paste a paragraph into a translator, get something that is roughly right, and start to wonder if the whole document will come out the same way: understandable, but not something you would sign or send.

Here is how to use AI to translate a document properly: pick the tool by what matters most. If the layout has to survive, upload the file to a document translator (Word’s built-in Translate, Google Translate or DeepL). If the wording, tone and terms have to be right, use ChatGPT or Claude with a prompt that tells it who will read it, which terms to keep, and to flag anything it is unsure about. Then check the result before anyone relies on it, and use a certified human translator for anything official.

That is the whole method. Below you get the tool choice, the prompt, how to handle long PDFs and Word files, how to keep confidential documents safe, and where AI translation stops being good enough.

Two kinds of AI translation, and when to use which

Most frustration comes from using the right tool for the wrong job. There are two families, and they are good at different things.

Document translators: keep the layout

These take a whole file and give you back the same file in another language, with headings, tables and bullet points where they were.

• Microsoft Word. Go to Review, then Translate, then Translate Document. Word opens a translated copy in a new window and leaves your original alone. It needs a Microsoft 365 subscription or Office 2021 and an internet connection (Microsoft Support: Translate text into a different language).
• Google Translate. On a computer, open Google Translate and choose Documents. It takes .docx, .pdf, .pptx and .xlsx files up to 10 MB, and PDFs up to 300 pages. Text inside images and scanned PDF pages is not translated (Google Translate Help: Translate documents).
• DeepL. A free account translates Word, PowerPoint and PDF files up to 5 MB or 100,000 characters, and those translated files are not editable without a paid plan (DeepL Help Center: File formats).

Use these when the document is long, the structure matters, and “correct and readable” is good enough: an internal manual, a supplier’s spec sheet, a report you only need to understand.

Chat assistants: get the wording right

ChatGPT and Claude read the document and write the translation like a person would, so you can steer them. You can tell them the reader is a nervous first-time customer, that “onboarding” must stay in English, that the tone is informal Dutch “je” and not formal “u”. A document translator cannot take any of that into account.

• ChatGPT accepts DOCX, PDF and TXT, plus spreadsheets and PowerPoint files. Documents can be up to 512 MB and 2 million tokens per file, and free users can upload 3 files per day (OpenAI Help: Uploading files to ChatGPT).
• Claude accepts PDF, DOCX, TXT, RTF, ODT and more, up to 20 files per chat. It reads text and visuals in PDFs up to 100 pages, and text only from 101 to 1000 pages (Claude Help Center: Upload files to Claude).

Use a chat assistant when the words will be read by a customer, a partner or a boss: a proposal, a website page, a policy, a sales email sequence.

My own habit, working between Dutch and English most weeks: I run the long, dry stuff through a document translator, and anything with my name on it goes through a chat assistant with the prompt below. Then I read it out loud. That last step catches more than any tool.

Step 1: Get the document ready (2 minutes)

Bad input gives bad translations. Before you upload anything:

• Check that the text is real text. Try to select a sentence in the PDF. If you cannot, it is a scan, and Google Translate will leave it untranslated. ChatGPT and Claude can usually read a clear scan, but check names and numbers extra carefully.
• Google Docs users: ChatGPT cannot take a .gdoc file. Export it as PDF or DOCX first.
• Write down your fixed terms. Product names, job titles, legal terms your company uses, words that must stay in the original language. Five to ten lines is plenty. This is your glossary.
• Know your reader. One sentence: who reads this, and what do they need to do after reading it?

Step 2: The prompt to paste

Upload the file to ChatGPT or Claude, then paste this. Fill in the square brackets once and save it, so every document your team translates sounds the same.

Translate the attached document from [source language] into [target language].

Reader: [who reads it, e.g. new customers in Spain who are not technical].
Tone: [e.g. friendly and clear, informal "tú" form].

Rules:
* Translate everything, including headings, tables and footnotes. Do not summarise or skip parts.
* Keep the same structure: same headings, same order, same lists.
* Keep these terms exactly as written: [glossary terms].
* Keep all names, numbers, dates, amounts and SKUs exactly as in the original. Convert date formats to the [target country] style only if I say so.
* Where a sentence is ambiguous or has no clean equivalent, translate it as best you can and mark it with [CHECK] plus a short note in English on why.

Start with the first [3 pages / 2,000 words]. I will say "next" for the rest.

Three lines do most of the work. “Do not summarise or skip parts” stops the model from quietly shortening long sections. “Keep all names, numbers, dates” protects the details that cause real damage when they change. And the [CHECK] marks turn the model’s doubts into a short list for you, instead of a confident guess buried in paragraph nine.

Step 3: Long documents, in chunks

Even when a tool accepts a big file, asking for 40 pages in one answer is where things go wrong: the reply gets cut off, or later sections come back shorter than the original. Work in pieces.

1. Ask for the first few pages, as in the prompt above.
2. Type “next” for each following chunk, in the same chat, so your rules and glossary stay in place.
3. Every few chunks, ask: “List any term you translated in two different ways so far.” That catches drift, like “invoice” becoming two different words halfway through.
4. Paste the chunks into one document at the end and compare the length with the original. A section that is much shorter is the first place to look for something skipped.

For very long PDFs in Claude, remember the split: up to 100 pages it also reads charts and images, from 101 pages it reads the text only. If your figures carry labels that need translating, upload those pages separately.

Step 4: Check it before anyone relies on it

AI translations read smoothly, and that is exactly the risk. OpenAI’s own help page says ChatGPT can produce incorrect or misleading output, sometimes with confidence, and advises treating it as a first draft and verifying important information (OpenAI Help: Does ChatGPT tell the truth?). A fluent sentence that says the wrong thing is worse than a clumsy one, because nobody stops to question it.

A check that fits in ten minutes:

• Numbers, names and dates. Put the original and translation side by side and compare every figure. This is boring and it is the most important part.
• Every [CHECK] mark. Decide each one yourself, or ask a colleague who speaks the language.
• Back-translate the risky parts. Open a new chat, paste the translated version of a key paragraph, and ask for a translation back into your language. If the meaning shifted, you have found a problem. It does not prove the translation is perfect, but it is a quick way to spot a big error.
• A native speaker for anything public. Five minutes of their time on the final version is worth more than any prompt.

Translating a PDF or Word document without losing the formatting

This is the most common question, and the honest answer is: chat assistants are not great at it. ChatGPT and Claude give you the text in the chat, and you rebuild the layout yourself.

Two ways to get both good wording and the original layout:

1. Translate the file first, polish second. Run the document through Word’s Translate Document or Google Translate so the layout comes back intact. Then paste the key sections (intro, anything customer-facing) into ChatGPT or Claude with your tone and glossary, and replace those parts in the translated file.
2. Ask for a file back. If your ChatGPT or Claude plan can create files, ask it to “return the translation as a .docx with the same headings and tables”. Check the result carefully: complex tables, text boxes and headers often move.

For a scanned PDF, neither family will keep the layout well. Ask a chat assistant for the text, check it, and drop it into a clean template.

Confidential documents: what to switch on first

Contracts, HR files and client data deserve a minute of thought before you upload them.

• On a personal ChatGPT Free, Plus or Pro account, your chats can be used to improve OpenAI’s models by default. You can turn that off under Settings, then Data controls, then “Improve the model for everyone”. Temporary chats are not used for training and may be kept for up to 30 days for safety (OpenAI Help: Data controls in ChatGPT).
• On ChatGPT Business or Enterprise, OpenAI does not use workspace content for training by default (same source).
• Follow your company’s rules first. If your employer has a policy on AI tools or an approved tool, that wins. When in doubt, remove names, account numbers and addresses before uploading, and put them back afterwards.

When AI translation is not enough

Some documents need a human translator, no matter how good the AI version reads.

• Official and legal submissions. For example, US immigration rules require any foreign-language document submitted to USCIS to come with a full English translation that the translator certifies as complete and accurate, plus a statement that they are competent to translate (8 CFR 103.2(b)(3)). Other authorities have their own rules, so check before you submit.
• Contracts you will sign. Use AI to understand the document, so you know what to ask. Let a lawyer or professional translator confirm the version that counts.
• Medical, safety and product instructions where a wrong word can hurt someone.

Even then, the AI draft saves time: you arrive at the professional with your questions ready.

A worked example

Say you run a small webshop and want your two-page returns policy in Spanish. Here is how the steps play out:

1. Prep: the policy is a Word file. Glossary: the shop name stays as is, “store credit” becomes one fixed Spanish term you choose, the 30-day window and the address stay exactly the same.
2. Prompt: reader is “Spanish customers who want to send something back and are a bit annoyed”, tone “calm, friendly, informal tú form”.
3. Result: the model returns the policy plus two [CHECK] marks, for example on a phrase it could translate in two ways. You pick one for each.
4. Check: you compare the numbers, back-translate the refund paragraph, and ask a Spanish-speaking friend or customer to read it once.
5. Publish: paste it into your shop. Save the prompt and glossary, so the shipping page next week sounds the same.

Common mistakes

• Pasting a long document with no instructions. You get a translation for nobody in particular, often slightly shortened.
• Trusting fluency. Smooth sentences are not the same as correct ones. Check the facts.
• A new chat for every chunk. Your glossary and tone get lost, and terms drift. Keep one chat per document.
• Forgetting the reader’s country. Spanish for Spain and for Mexico differ, so do Portuguese for Portugal and Brazil. Say which one in the prompt.
• Uploading client data without thinking. Check your data settings and your company rules first.

Frequently asked questions

Can ChatGPT translate documents?

Yes. Upload a Word file, PDF or text file and ask for a translation into the language you need. It is strongest on wording and tone. It gives you the text in the chat rather than a formatted copy, unless your plan lets it create files.

Is there a free way to translate a document with AI?

Yes. Google Translate’s Documents option is free for files up to 10 MB, a free DeepL account allows smaller Word, PowerPoint and PDF files, and ChatGPT’s free plan allows 3 file uploads per day. Limits change, so check the help pages linked above.

Can Claude translate a PDF?

Yes. Upload the PDF and use the same prompt. Claude reads text and visuals in PDFs up to 100 pages and text only from 101 to 1000 pages.

Is AI translation accurate enough for work?

For understanding a document and for most everyday business writing, it is usually a strong first draft. For anything official, legal or safety-related, treat it as a draft that a qualified human checks. The tools themselves tell you to verify important information.

Which is better for translation, ChatGPT or Claude?

Both do this well when you give them a clear reader, tone and glossary. Try the same page in both and keep the one that sounds more natural to you. Our comparison of ChatGPT vs Claude for writing covers the differences in style.

Legal wording is the part of a translation where mistakes cost the most. If you are working with contracts or similar paperwork, read how to use AI for legal documents safely before you rely on any translated clause.

Where to go from here

Translation is often step one. Once the text is in your language, you can let AI do the rest of the work: analyze a long PDF with Claude, summarize a long document for work, or make your reply email sound more professional before you send it back.

Today, take one real document from your inbox. Write a five-line glossary, run the prompt, check the numbers. You will know within ten minutes whether this saves you time.

If you want more small, practical wins like this one, using AI for the real tasks on your desk, start with the free Launchpad on our home page.