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Reduce PDF File Size

Reduce PDF file size with quality control — choose Max Compression, Balanced or High Quality mode. Each page is rendered via PDF.js and re-encoded as JPEG using the Canvas API, then assembled into a new optimised PDF by pdf-lib. No uploads, no server, no watermarks.

✓ 3 Quality Modes ✓ PDF.js Page Rendering ✓ Canvas JPEG Re-encoding ✓ Before/After Size Comparison ✓ No Server Upload ✓ No Watermarks

PDF File Size Reducer

Upload a PDF, choose quality level, then reduce — all in your browser

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Drop your PDF here

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Processed entirely in your browser · File never uploaded to any server · Free forever

🔒 Powered by PDF.js & pdf-lib (open-source) · Your file never leaves your browser · No API, no server

How PDF Size Reduction Works

Parse PDF

PDF.js loads and parses your PDF in-browser, reading all pages, fonts, images and vectors.

Render to Canvas

Each page is rendered at your chosen scale (1.0×–1.5×) to an HTML canvas element — creating a pixel-perfect raster image.

JPEG Re-encode

The Canvas API encodes each page as JPEG at your quality setting (40%, 65% or 82%), significantly reducing image data size.

Assemble & Download

pdf-lib creates a new PDF, embeds each JPEG image at the correct page size, and generates the download — no server involved.

Quality Mode Comparison

Mode	JPEG Quality	Page Scale	Typical Size Reduction	Best For
🗜️ Max Compression	40%	1.0×	60–80%	Email attachments, web upload limits
⚖️ Balanced	65%	1.2×	40–65%	General use, sharing documents
🔍 High Quality	82%	1.5×	20–45%	Archiving, print-quality preservation

Frequently Asked Questions

How does this PDF file size reducer work?

The tool renders each PDF page to a canvas using PDF.js, then re-encodes the canvas as a JPEG at your chosen quality (40%, 65% or 82%). These JPEG images are embedded into a new PDF built by pdf-lib. This technique genuinely reduces file size by re-encoding image content at a lower quality. All processing is entirely client-side — your file never leaves your browser.

Which quality mode should I choose?

Max Compression gives the smallest output file — ideal for emailing or uploading where file size limits are strict. Balanced is the best default for most uses — significant reduction with good readability. High Quality minimises visual degradation — use this when the PDF contains fine print, technical diagrams or photography.

Will text still be selectable after reduction?

No — the page-rendering approach rasterises each page into an image. Text is visually preserved but is no longer selectable or copy-pasteable. If you need to keep the selectable text layer while still reducing file size, use the Compress PDF tool instead, which does structural lossless compression.

Are my files uploaded to a server?

No — your files never leave your device. PDF.js renders pages in your browser, the Canvas API JPEG-encodes them, and pdf-lib assembles the output — all client-side. No API calls, no server, no data sent anywhere.

About ToollLive Free PDF File Size Reducer

ToollLive's free reduce PDF file size tool is the most effective way to reduce PDF size online with quality control. Upload any PDF and choose from three modes — Max Compression, Balanced or High Quality. The tool uses Mozilla's PDF.js to render each page to canvas, then the browser's Canvas API to re-encode pages as JPEG at your chosen quality, before pdf-lib assembles the final optimised PDF. This approach achieves 20–80% PDF size reduction depending on the original file and quality setting. Unlike lossless compressors, this PDF file size reducer can dramatically shrink PDFs with embedded images. No sign-up, no watermarks, no server uploads. Also try Compress PDF (lossless), Combine PDFs and Rearrange PDF Pages.