Reduce PDF file size with quality control
Most oversized PDFs are oversized for one of two reasons: embedded raster images are stored at much higher resolution than the output ever displays, or the same data is stored multiple times (duplicate fonts, uncompressed content streams, editor history that was never cleaned up). A 50 MB PDF of a 30-page report is almost always 45 MB of high-DPI photos embedded at print resolution plus 5 MB of everything else. Understanding this ratio explains why compression levels behave the way they do: "high" compression does not mean lossier encoding of text; it means more aggressive downscaling of embedded images and switch to lossy JPEG for images that were stored as lossless. This compressor exposes that behavior directly. Low compression reduces image DPI from whatever they were embedded at down to 300 DPI (print quality), which often saves 30-50% for documents with high-resolution photos and nothing for text-only documents. Medium compression drops to 150 DPI (screen quality), typically saving 60-75% on image-heavy documents, the tradeoff is that pinch-zooming past about 200% on screen will start to look soft. High compression goes to 72-96 DPI and re-encodes images as JPEG at quality 60-70, saving 80-90% on photo-heavy PDFs but visibly degrading image quality at any zoom level.
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Compress images to reduce file size while maintaining visual quality. Supports lossy and lossless compression with real-time preview and size comparison.
Compress videos up to 90% smaller without visible quality loss. Multiple quality presets, resolution scaling, and bitrate control. Perfect for email, social media, and web uploads.
Add your signature to PDF documents. Draw, type, or upload your signature, then position it anywhere on the page. Perfect for contracts, agreements, and official documents.
A 28 MB brochure exceeds an upload portal’s 10 MB limit.
Input
brochure.pdf 28 MB · downsample images to 150 DPI
Output
brochure.pdf ≈ 7 MB, text crisp, images still print-acceptable
Most PDF bloat is over-resolution images; downsampling and re-compressing them (while leaving vector text untouched) is what produces a large size cut without fuzzy type. A preview confirms images are still acceptable before you commit.
Most oversized PDFs are oversized for one of two reasons: embedded raster images are stored at much higher resolution than the output ever displays, or the same data is stored multiple times (duplicate fonts, uncompressed content streams, editor history that was never cleaned up). A 50 MB PDF of a 30-page report is almost always 45 MB of high-DPI photos embedded at print resolution plus 5 MB of everything else. Understanding this ratio explains why compression levels behave the way they do: "high" compression does not mean lossier encoding of text; it means more aggressive downscaling of embedded images and switch to lossy JPEG for images that were stored as lossless. This compressor exposes that behavior directly. Low compression reduces image DPI from whatever they were embedded at down to 300 DPI (print quality), which often saves 30-50% for documents with high-resolution photos and nothing for text-only documents. Medium compression drops to 150 DPI (screen quality), typically saving 60-75% on image-heavy documents, the tradeoff is that pinch-zooming past about 200% on screen will start to look soft. High compression goes to 72-96 DPI and re-encodes images as JPEG at quality 60-70, saving 80-90% on photo-heavy PDFs but visibly degrading image quality at any zoom level.
Shrink a PDF below common email size limits so it can be sent without a file-sharing link.
Reduce file size for faster downloads when hosting PDFs on a website.
Compress archived documents to free up disk space without losing important content.
The compression pipeline processes each image object in the PDF's resource dictionary. For each image it computes the display DPI at the current page size (a 2400x3000 pixel image placed in a 6x8 inch region is displaying at 400 DPI) and compares to the target DPI for the selected compression level. If the source DPI exceeds the target, the image is downscaled using bicubic resampling and re-encoded. If the source was lossless (Flate-compressed raw pixels or PNG), it may be re-encoded as JPEG at the target quality, which typically saves 60-80% on photographic content. Images already below the target DPI are left untouched.
Text and vector content are not touched by image compression. Vector paths are stored as drawing instructions, not pixels, so they are already as efficient as they can be at any zoom level; that is why compressed PDFs zoom to arbitrary sizes without getting pixelated on text while images degrade. The compressor also removes redundant objects: duplicate fonts embedded multiple times (common when PDFs are assembled from documents that each embed their own copy of the same font), unused form field dictionaries, and thumbnails for pages that do not need them. This "object-level" cleanup typically saves 10-15% on heavily assembled documents.
One trap to watch for: JPEG2000-encoded images (common in professional print workflows) can survive the compression pass unchanged even at "high" settings, because re-encoding them as JPEG would actually increase file size at equivalent quality. If your document is already near its optimal size, the compressor may report only a few percent of savings and that is correct behavior, there is no magic to extract when the document was already well-optimized upstream. The most dramatic savings come from files exported from Word or similar office tools, which often embed screenshots and photos at 600+ DPI regardless of display size; those commonly compress 70-85% at medium settings with no visible quality difference.
It depends on the content. PDFs with many high-resolution images can often be reduced by 50-80%. Text-heavy documents see smaller reductions.
No. Text and vector graphics remain crisp. Only embedded raster images are optimized.
You can try, but the size reduction will be minimal if the file has already been optimized.
PDF parsing and editing happen in your browser. Documents, and everything inside them, are never uploaded or stored remotely.