OCR settings: Tesseract.js 7.0.0, LSTM engine, automatic page segmentation (PSM 3), render scale up to 3 with the longer image side capped at 2,400 pixels. Each one-page Letter scan renders to 1,836 × 2,376 pixels. English or Simplified Chinese + English is selected explicitly. The OCR entry script, worker, engine and selected language data load only after conversion reaches an image-only page with local OCR enabled.
Opening this page or converting a text-layer PDF does not request these OCR files. Bundled file sizes are 62,961 bytes for the OCR entry script, 2,952,873 bytes for the English language pack and another 1,718,768 bytes for Simplified Chinese; engine files add several megabytes. These are stored file sizes, not memory usage.
The measured network transfer for a first uncached English OCR run and for a repeat run is given under “Measured click-to-result OCR time and network transfer” above; actual transfer depends on the engine variant, compression and cache. The first scan conversion requires extra downloads and initialization; later runs may benefit from the browser HTTP cache, but a new worker is initialized for each conversion.
Worker execution keeps recognition off the main thread, but PDF rendering, model loading and OCR still use device memory, CPU and battery and can make a phone warm or slower. Pages are processed sequentially, render size is capped and the worker is terminated after success or failure. This does not guarantee a responsive phone or constant memory use. These tests do not establish phone speed or peak memory.
Convert PDF to TXT without uploading
Choose one PDF with a text layer or image-only scan, review the extracted text, then download its TXT file. PDF.js reads the selected local bytes in this browser. Code, workers, CMaps, standard fonts and OCR language data load from this site; your selected document is not sent to a conversion server. No account, model call or paid conversion API is involved.
Limits before you start
This tool extracts existing PDF text and can recognize image-only pages with local OCR. For scanned PDF to text, keep local OCR enabled and select the printed language. PDF to text OCR runs inside this browser. Mixed pages with an existing text layer use that layer; words inside their images can remain unrecognized. OCR disabled, empty OCR results or a failed page stop the whole file; no partial TXT is presented as a complete document. Rotated pages/text, font-defined vertical writing and encrypted PDFs are rejected.
One file per run; input up to 30 MB, 60 source pages for text extraction or 10 source pages when OCR is needed ; 500,000 extracted characters per run. There is no daily account quota. OCR languages currently available: English and Simplified Chinese + English; other languages are not offered. A 90-second timeout check occurs between pages, so a difficult individual page can still occupy your browser longer. Images, forms, annotations, hyperlinks as interactive objects and the original page design are not exported. Existing PDF text may itself be incomplete or incorrectly encoded.