Tool by tool: who it suits and what to watch
OmniDoc free document translator ours
PDF and LaTeX come back as a bilingual version and a translation-only version; Word, Excel, EPUB and the rest come back as translated files that keep paragraphs, tables and styles; PowerPoint as a translated deck (no bilingual version for slides yet). Only you can see the files you upload and their results. For more than 2000 pages, or when you are in a hurry, the desktop app for Windows, macOS and Linux has no page limit and no queue.
Good for: long documents, papers (PDF or LaTeX source), and anyone who checks the translation against the original.
DeepL
DeepL’s plan page lists 1 file translation per user per month on the free plan, with files up to 5 MB; the paid individual plan has 3 a month. The translation quality is well regarded, but the allowance is counted in files, so it suits the odd short document.
Good for: one or two small files a month where wording matters.
Source: DeepL — Plans and pricing
Google Translate (website)
Google’s help page says the website translates .docx, .pdf, .pptx and .xlsx files up to 10 MB, and PDFs must have 300 pages or fewer; text in images and scanned PDF pages is not translated. For larger or more files Google points to the Cloud Translation API.
Good for: Office files and PDFs with a text layer, under 300 pages.
Source: Google Translate Help — Translate documents & websites
Yandex Translate
Yandex’s help page lists DOC, DOCX and PDF text files, XLS and XLSX spreadsheets and PPT and PPTX presentations; a file must not exceed 5 MB, and the translation is saved in the original format. It is strong between Russian and the languages of the region.
Good for: small files in Russian, Ukrainian, Kazakh and nearby languages, including old .doc, .xls and .ppt.
Source: Yandex Translate Help — Translating documents
Immersive Translate
Its PDF translator page says free users can translate up to 1,000 pages a month and Pro users 10,000, with a side-by-side bilingual or a translation-only result. Its main strength is bilingual web pages in the browser extension.
Good for: people who already use its browser extension and translate under 1,000 pages a month.
Source: Immersive Translate — PDF Translator
Smallpdf
Its Translate PDF page lists more than 20 languages and OCR for scanned files, and says the original formatting is kept as much as possible, while images and special layouts do not carry over. Unlimited use starts with a 7-day trial.
Good for: a one-off PDF without creating an account.
Source: Smallpdf — Translate PDF
PDFMathTranslate (pdf2zh)
An open-source project that keeps formulas, charts, the table of contents and annotations, and writes a translation-only PDF and a bilingual PDF. It comes as a command line tool, a GUI, Docker, a Windows app and a Zotero plugin; it uses Google Translate by default and can use DeepL, Ollama, OpenAI and others.
Good for: translating papers with formulas on your own computer, if you are happy to install software.
Source: PDFMathTranslate — GitHub README
Microsoft Word (built-in Translate)
Review > Translate > Translate Document opens a translated copy in a new window. Microsoft’s support page says the feature is for Microsoft 365 subscribers and Office 2021, and needs an internet connection with connected experiences turned on. If you already pay for Microsoft 365, it is the shortest route for Word files.
Good for: Word files, when you already have Microsoft 365.
Source: Microsoft Support — Translate text into a different language
OmniDoc Free Document Translation