Compress PDF
Make PDFs smaller for email and uploads. Pictures inside the document are downscaled and re-encoded on your device; text stays text.
How to compress a PDF without uploading it
- Add one or more PDFs. Each row shows the page count and a preview of the first page.
- Pick a level. Balanced suits email and web uploads; Light keeps print detail; Strong is for hard size limits. Keep the default Keep text method unless the file is a scan whose pictures could not be re-encoded.
- Click Compress, compare the sizes in the result rows, and download one file, a ZIP, or send the results to Merge PDF or Split & Organize.
A PDF that is mostly text has little to compress; the result may be the original file. The savings come from photos and scans.
Open the downloaded PDF and check the pictures before sharing. Compression creates a new file; your original is unchanged.
Useful details
Are my PDFs uploaded?
No. Reading, previewing and compressing happen in your browser. File contents and filenames are not sent to Toolkitta. Keep this tab open until you download the result; reloading clears the session. Website hosting and performance measurement are described in our Privacy notice.
Does compressing reduce quality?
Yes, for pictures: they are re-encoded as JPEG, which is lossy, and downscaled when they have more pixels than the chosen level allows. Text, fonts and vector drawings are not changed with the Keep text method. Choose Light for print, Balanced for screens, Strong for tight limits, and compare the result before sharing. Your original file is not modified.
Why is my PDF not smaller?
The size of a PDF comes mostly from its embedded pictures. A text-only document, a file whose pictures are already small, or a scan stored as JPEG 2000, CCITT or JBIG2 has little the Keep text method can shrink; the row then reports pictures left unchanged, and the original bytes are returned if the rewrite would not be smaller. For such scans, try Flatten pages, which renders each page as a JPEG picture.
What does Flatten pages do to my document?
Each page is rendered at the level's resolution and stored as one JPEG image on a page of the same size. The result opens anywhere and is usually much smaller for scans, but text is no longer selectable or searchable, links and form fields are gone, and fine print can soften. Use it deliberately, and keep the original.
What are the limits, and which files are not supported?
Up to 20 PDFs, 50 MB each and 200 MB combined; files over 300 pages are skipped. Encrypted or password-protected PDFs, XFA forms and digitally signed documents are rejected with an explanation: export an unencrypted, unsigned copy from your PDF application first. Large documents use considerable browser memory; if your device struggles, compress fewer files at a time.
Is metadata, are forms or bookmarks removed?
No. Document metadata, bookmarks, links, form fields and annotations are kept with the Keep text method; unused leftover objects from earlier edits are dropped. This is not a metadata-removal, sanitization or redaction tool. Flatten pages keeps only the page pictures. Review the result before distributing it.
What changes, and what does not
A PDF is a container. Text is stored as characters plus fonts, drawings as vector instructions, and photos or scans as embedded images. The images are almost always the bulk of the file, so that is where this tool works: each supported picture is decoded, scaled so it has no more pixels than the chosen level needs for the largest page, and re-encoded as JPEG. Text, fonts and vector graphics are copied into the new file unchanged, and the file structure is rewritten without leftovers from earlier edits.
How the levels map to pixels
- Light: pictures capped at 300 dpi across the page, JPEG quality 85. Suitable for printing.
- Balanced: 150 dpi, quality 75. Sharp on screens and phones; the usual choice for email and web forms.
- Strong: 100 dpi, quality 60. Text in scans stays readable; fine detail in photographs softens.
A 300 dpi A4 scan is about 2480 × 3508 pixels. At Balanced it becomes at most 1240 × 1754 pixels, a quarter of the pixels, and JPEG at quality 75 typically stores that page in a few hundred kilobytes. Pictures that are already small are never enlarged, and any picture whose re-encoded version would not be smaller is left exactly as it was.
When to flatten instead
Some scanners store pages as JPEG 2000, CCITT fax or JBIG2 images, and some designs use CMYK or indexed colour. The Keep text method leaves those pictures unchanged and tells you how many. Flatten pages renders every page as one JPEG picture at the level's resolution instead, which works for any PDF at the cost of selectable text. Use it only when the result row reports pictures it could not re-encode, and check readability before sharing.
Need to combine files first? Merge PDF keeps original page content; compress the merged result here. For photos, the Image Compressor works on the pictures directly.