Manuscript PDF too large to upload: limits and how to shrink it

Typical size limits

Submission portals cap uploads, and the cap is usually the whole reason a manuscript bounces.

• arXiv: 50 MB for the whole submission
• Most journal and conference systems: a per-file limit that commonly falls between 10 and 50 MB, stated on the upload page
• Supplementary material often has its own, smaller limit
• Email-based submissions to editors or reviewers usually fail above about 20 MB

Why a 12-page paper weighs 80 MB

Text is tiny. Almost all of the size comes from figures: uncompressed TIFF or PNG screenshots at print resolution, vector plots with hundreds of thousands of points, photographs pasted at camera resolution, and embedded fonts duplicated in every figure file. A single microscopy image can outweigh the rest of the document.

Shrink the figures first

The largest wins come from the source, before the PDF exists.

• Export raster figures at 300 dpi for print and 150 dpi for review copies, not screen-capture size
• Use JPEG for photographs and PNG only for line art and screenshots
• Rasterize scatter plots with millions of points instead of embedding them as vectors
• Downsample images when exporting from Word, LaTeX, or Google Docs, if the exporter offers it

Then compress the PDF itself

PaperKit Compress PDF rewrites the file with compressed object streams and strips redundant metadata, all in your browser. It helps most with bloated exports and files that were merged many times. Files dominated by high-resolution photos need the images downsampled at the source; a structural rewrite alone will not get an 80 MB photo-heavy file under 10 MB.

Keep the review copy private

Online compressors upload your unpublished manuscript to their server. PaperKit does the rewrite locally, so the file is never transmitted, and you can combine it with Remove PDF Metadata and Delete PDF Pages in the same tab before you submit.