100% local · no uploads · free

OCR a Scanned PDF

You scanned a stack of old receipts, a textbook chapter, or years of paper records into PDF. Now you need to find one specific invoice from 2023 — but Ctrl+F does nothing because the PDF is just pictures of pages. It has no searchable text layer.

OCR (Optical Character Recognition) solves this by reading the text in each page image and adding an invisible, selectable text layer on top. After OCR, you can search, copy, and extract text from the document as if it were born digital.

Most OCR tools require uploading your documents to a cloud server for processing. For personal records, financial documents, or anything sensitive, that is a dealbreaker. KuroPDF runs the entire Tesseract OCR engine locally in your browser using WebAssembly. Your scanned documents never leave your device — not a single page, not a single word.

The engine supports 100+ languages and processes pages in parallel using Web Workers, so a 50-page document completes in a couple of minutes on a modern device. The result is a standard PDF with an embedded text layer that works in every PDF reader.

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  • Files never leave your device
  • No size limits
  • Free, no sign-up

Frequently asked questions

What languages does the OCR support?

Tesseract OCR supports 100+ languages including English, Spanish, French, German, Italian, Portuguese, Dutch, Russian, Chinese (simplified and traditional), Japanese, Korean, Arabic, Hindi, and many more. Common languages load automatically.

How accurate is the text recognition?

Accuracy depends on scan quality. Clean, straight scans at 300 DPI typically achieve 95-99% accuracy. Skewed, low-resolution, or handwritten text will produce lower accuracy. The engine works best with typed/printed text.

Is my scanned document uploaded anywhere?

Everything runs locally in your browser using WebAssembly. Because no data is uploaded to a cloud server, your files remain strictly private, and the entire process generates zero server carbon emissions, making it highly eco-friendly.

How long does OCR take?

About 2-5 seconds per page on a modern device. A 50-page document processes in 2-4 minutes. Pages are processed in parallel using Web Workers for maximum speed.

Can I search the PDF after OCR?

Yes — the OCR result is a standard PDF with an invisible text layer. You can search with Ctrl+F, select and copy text, and the document remains fully searchable in any PDF reader.

Does OCR change how the PDF looks?

No. The visual appearance is identical. OCR adds an invisible text layer behind the page images — it does not alter the images themselves.

The real difference

Why KuroPDF exists

Every other PDF tool uploads your files to their servers. We think that is broken. Here is what we do differently - and what the alternatives actually cost you.

Nothing leaves your device

Files are processed in your browser using WebAssembly. Open DevTools → Network tab and verify: zero upload requests. Ever.

What competitors do instead:

Smallpdf, iLovePDF, and Adobe Acrobat all upload your files to their servers - your contracts, bank statements, and medical records pass through third-party infrastructure.

No file size limits, no daily caps

Process a 500-page PDF or batch-convert 200 photos. No cap, no throttle, no upgrade wall. Your device is the only limit.

What competitors do instead:

Smallpdf limits free users to 2 tasks per day. iLovePDF caps file sizes at 100MB. Adobe requires a $19.99/mo subscription for basic features.

Works completely offline

Install KuroPDF as a progressive web app. After the first visit, every tool works with zero internet - on a plane, in a bunker, wherever.

What competitors do instead:

Every cloud-based PDF tool stops working the moment your Wi-Fi drops. No connection = no work.

Real encryption, not security theatre

Password protection uses AES-256 encryption via a WebAssembly build of qpdf. The password never leaves your machine - there is no server to intercept it.

What competitors do instead:

When you 'protect' a PDF on Smallpdf or iLovePDF, your unencrypted file and password travel to their server, get processed, then get sent back. That is not security.

Free forever, no account needed

No login wall, no email harvesting, no 'continue with Google' popup. Open the site, use the tool, close the tab. Done.

What competitors do instead:

Adobe charges $239/yr. Smallpdf charges $108/yr. iLovePDF charges $84/yr. All require account creation to use basic tools.

Professional-grade codecs

MozJPEG for JPEG, OxiPNG for PNG, AVIF and WebP encoders - the same codecs used by Google and Mozilla. Not generic re-encoding.

What competitors do instead:

Most cloud tools use basic server-side encoders with less optimization control. You get worse compression at lower quality.

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