How to Detect a PDF's Language Online — Free, 100+ Languages

Someone forwarded you a PDF and you can't tell if it's Uzbek Cyrillic or Russian. A pipeline needs to route documents to language-specific OCR models. Detecting the language first means running the right OCR on the second pass.

When you actually need Detect Language

Document pipelines that need to route by language, archives mixed with multiple scripts, translation services pre-classifying input, multilingual customer support triaging tickets.

How to detect language, step by step

Open the tool

Go to convertpdfgo.com/ocr-detect-lang. No account, no email, no installation.

Drop the file in

Drag the file onto the upload area or click to pick. Files up to 30 MB go through without a queue. Encrypted in transit (TLS 1.3), encrypted at rest, deleted within one hour.

Configure

Nothing to configure — Tesseract runs automatically and returns the language code.

Download

Open in any reader, paste anywhere, feed to scripts.

Common problems and how to avoid them

Mistakenly classified as wrong language

Close scripts confuse the classifier. Cyrillic Uzbek and Russian are most often swapped — verify against a known sample if in doubt.

Returns 'eng' for a non-English doc

Most Tesseract installations default to English when uncertain. If your scan is too low quality, the detector falls back to the default model.

Doesn't return any language

Tesseract requires some recognisable text. Truly blank or all-image (no OCR layer) PDFs return empty.

A short word on privacy

Three things to know. One: files go over TLS 1.3. Two: files are encrypted at rest while we process them, then deleted automatically within one hour. Three: we don't look at your files or train on them.

How we compare to other free tools

Feature	convertpdfgo	Smallpdf	iLovePDF
Sign-up	None	After 2/day	Optional
Watermark	None	None	None
Auto-delete	1 hour	Vague	2 hours

Frequently asked questions

Does it work on mixed-language documents?

Yes — it returns the dominant language. For balanced bilingual docs (Uzbek + Russian, say), expect the more text-heavy script.

How accurate?

Very high on clean scans — Tesseract distinguishes between similar scripts (Cyrillic Russian vs Cyrillic Uzbek) reliably.

Are my files private?

Files are encrypted in transit (TLS 1.3) and at rest, then auto-deleted within one hour.

Will it work on protected PDFs?

Not directly — unlock the PDF first with our Unlock PDF tool if you know the password.

Is there a usage limit?

No. Free, no daily cap, no sign-up wall, no watermark.

How long does it take?

About 5-30 seconds depending on file size and OCR complexity. Multi-page scans take longer.

What's the file size limit?

30 MB as a guest, 50 MB when signed in.

What to do next

Now you can OCR PDF, OCR Extract Text, or Inspect PDF. All free.

Or browse our full list of 49 free PDF tools.