Compress a PDF
Lighter for email, still sharp on screen.
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How to compress a PDF, step by step
Four compression levels, each with a different trade-off on the document’s weight and text: you choose knowing what you give up.
Drop in the PDF to compress
The starting size appears right away; a password-protected file is refused.
Choose a level
“Recommended”, the default, recompresses oversized images and keeps the text selectable; “Light (lossless)” rewrites the file without touching the images. “Balanced” and “Maximum” rebuild every page as an image, at a more or less aggressive scale and JPEG quality.
Set the options and read the warnings
With “Recommended”, “Grayscale images” turns the images grey; “Remove metadata” works at every level. Balanced and Maximum warn that the text will no longer be selectable once the pages become images. “Target size” sets a maximum weight the tool tries to reach; “Remove annotations” deletes comments and highlights.
Click “Compress the PDF”
Processing happens entirely on your own device.
Compare and download
The result shows the size before and after, with the percentage gained, or lost if the original file was already highly optimised: “Keep the original” then downloads the starting file.
On an already well-optimised PDF, the result can be heavier than the original: VellumPDF says so plainly and offers to keep the original rather than hiding it.
Frequently asked questions
Which compression level should I choose to shrink a PDF?
“Recommended”, the default level, recompresses only oversized images (longest side brought down to 2000 pixels, JPEG quality 0.75) and keeps the text selectable. “Light (lossless)” rewrites the file without touching the images. “Balanced” and “Maximum” turn every page into a JPEG image, which saves more weight but makes the text unselectable. Start with “Recommended” and keep the last two for scans.
Does compression keep the text selectable?
Yes with “Recommended” and “Light (lossless)”, which leave the text alone: the first recompresses only the images, the second recompresses nothing. The “Balanced” and “Maximum” levels turn each page into an image, so the text is no longer selectable or searchable after compression.
Can VellumPDF compress a password-protected PDF?
No, an encrypted file must be unlocked first. Compression itself is free and computed on your device, without the document being sent to a server.
Why can the resulting file end up heavier than the original?
On an already optimised file, rewriting sometimes gains nothing: “Light (lossless)” can produce a slightly heavier result, and “Balanced” or “Maximum” often make a text-only PDF heavier. “Recommended” replaces an image only when its new version is lighter. When the result weighs more, VellumPDF shows it as a percentage and offers “Keep the original”.
Do the ‘Balanced’ and ‘Maximum’ levels compress only the document’s images?
No, they rasterise every whole page to JPEG, whether it originally held text or a scanned image, then rebuild a new PDF made only of those images. It is “Recommended” that compresses only the images: it leaves the text, the vector drawings and the images it cannot handle safely (CMYK colours, masked images, JPEG 2000, JBIG2) untouched.
What exact settings distinguish ‘Balanced’ from ‘Maximum’?
‘Balanced’ renders each page at a scale of 1.5 with a JPEG quality of 0.72; ‘Maximum’ drops to a scale of 1.1 and a quality of 0.5. The lower the scale and quality, the more the image loses sharpness and weight — a trade-off to weigh depending on whether your pages hold mostly fine text or simple photographs.
How do I get a PDF under a size limit set by an online form?
Tick “Target size” and enter the “Maximum size”, in KB or MB. VellumPDF then tries up to eight increasingly strong settings: first the images alone, the text staying text, and only as a last resort turning the pages into images, flagged by a warning. If the target stays out of reach, it says so and delivers the best result it got.
Can the images be turned to grayscale, or the metadata removed, while compressing?
Yes. With “Recommended”, the “Grayscale images” box turns the recompressed images grey, which suits a document meant for black-and-white printing. The “Remove metadata” box, available at every level, clears the title, author, subject, keywords, creator, producer, dates and XMP data. The “Remove annotations” box deletes comments, highlights and notes, keeping links and form fields.