Are my files uploaded to a server when I use this converter?

No. All file conversion happens entirely in your browser using JavaScript, WebAssembly, Canvas, and browser-native APIs. Unlike FreeConvert, Convertio, or iLovePDF (which upload your files to remote servers), Prescosoft Local File Converter never sends your data anywhere. Your files are read into local browser memory and the converted output is downloaded directly back to you. There is no upload endpoint in this tool.

What file formats can I convert?

Images: JPG, PNG, WebP, BMP, GIF, SVG, AVIF with resize, rotate, quality, and filter controls. Audio: MP3, WAV, AAC, OGG, M4A, FLAC. Video: MP4, WebM, MOV, AVI, MKV (via ffmpeg.wasm). Documents: PDF split/merge, TXT, HTML, Markdown, JSON, CSV, XLSX, DOCX text extraction. Archives: ZIP extraction and creation. Other: Base64 encode/decode, URL encode/decode.

Is there a file size limit?

There is no server-imposed file size limit since processing happens locally. The only constraint is your browser's available memory. Files over 1 GB are blocked to prevent tab crashes. For large video files (over 500 MB), the tool shows a confirmation warning. Modern desktop browsers with 8+ GB RAM handle most conversions comfortably.

How does the converter work without a server?

The converter uses browser-native APIs and client-side libraries: Canvas for image conversion, ffmpeg.wasm (WebAssembly) for audio and video conversion, PDF-LIB for PDF processing, SheetJS for spreadsheet conversion, and JSZip for archive handling. Heavy libraries like ffmpeg.wasm are lazy-loaded only when needed, keeping the initial page load fast.

Is this file converter really free?

Yes, 100% free with no account required, no premium tiers, no ads, no watermarks, and no file-count limits. Unlike many online converters that offer a free tier with restrictions and push paid plans for larger files or batch processing, Prescosoft Local File Converter gives full access to all features at no cost.

Can I convert multiple files at once?

Yes. You can drag and drop multiple files at once. Each file is processed locally in sequence with progress tracking and ETA display. PDF merge combines multiple PDFs into one document. ZIP creation packages multiple selected files into a single archive. All conversions can be cancelled at any time.

🔒 All processing happens in your browser. Nothing is uploaded.

Local File Converter — Convert Files Privately in Your Browser. No Upload.

Drop in images, media, PDFs, spreadsheets, archives, and text files. Convert, compress, preview, extract, resize, encode, and download without sending your files to a server.

Start converting View supported formats

local pipeline

1. Detect signature, MIME type, and extension

2. Preview using File API, Canvas, audio/video, PDF, or text readers

3. Convert through native browser APIs, PDF-LIB, SheetJS, JSZip, or ffmpeg.wasm

4. Download the output Blob directly from memory

📁

Drop files here or click to browse

Images, videos, audio, PDFs, documents, spreadsheets, archives, and text.

Large media conversions may need modern desktop browsers and enough memory.

Preview

No file

Choose a file to see a local preview.

Conversion setup

Target format

Smart routing: native Canvas is preferred for image conversions; ffmpeg.wasm is lazy-loaded for media; PDF-LIB, SheetJS, and JSZip load only when needed.

Progress

Idle

Ready. Files stay local.

Supported conversion workspace

The app prioritizes reliable local conversions.

Images

JPG, PNG, WebP, BMP, GIF first frame, SVG, AVIF where supported. Resize, rotate, quality, grayscale, contrast.

Audio & Video

MP3, WAV, AAC, OGG, M4A, FLAC, MP4, WebM, MOV, AVI, MKV, GIF through ffmpeg.wasm when available.

PDF & Documents

PDF page extraction and PDF merge when multiple PDFs are selected, TXT/HTML/Markdown conversions, simple TXT/HTML to PDF, basic DOCX text extraction, JSON formatting. PDF text/image extraction is intentionally not claimed in this app.

Spreadsheets

CSV, TSV, JSON, XLSX via SheetJS standalone browser build.

Others

Base64 encode/decode, URL encode/decode, text cleanup, JSON minify/beautify.

Why Local Conversion Matters

Most free online file converters — FreeConvert, Convertio, iLovePDF, ConvertFiles.com — upload your files to a remote server for processing. This creates real privacy and security risks, especially for confidential documents, personal photos, legal files, and business data.

🔴 Server-Upload Converters

Your files are sent to unknown servers. iLovePDF was exposed setting 637 cookies on users. Terms of service often grant broad rights to uploaded content. File metadata, contents, and conversion history may be logged, sold, or leaked.

🟢 Prescosoft Local Converter

Files are read into browser memory only and never leave your device. No upload endpoint exists in this tool. Zero cookies, zero tracking, zero server-side processing. Your confidential data stays confidential.

⚡ How It Works

Canvas API for images, ffmpeg.wasm (WebAssembly) for audio/video, PDF-LIB for PDFs, SheetJS for spreadsheets, JSZip for archives — all running locally. Smart routing picks the fastest method. No waiting for a server to respond.

Ideal for lawyers handling confidential case files, journalists protecting sources, healthcare workers with patient data, business professionals with proprietary documents, and anyone who values digital privacy.