Last updated:
What makes a PDF big is usually its pictures
A PDF’s size mostly comes from the images inside it: scanned pages, phone photos, large pictures in a presentation. Text and drawings are small next to them. So this tool touches the images only: each one is brought down to the pixels it needs at the size it is shown on the page, then recompressed.
What counts is the placement, not the image itself. A 4000-pixel photo placed 2 inches wide needs about 300 pixels for 150 DPI; a full-page scan keeps enough pixels for the whole page. An image used in two places is sized for the larger one.
The text stays selectable
Some compressors turn every page into a picture: the file shrinks, but the text can no longer be selected, searched or read by a screen reader. Here text, fonts, links, bookmarks and form fields stay exactly as they are, and the page count, order and size do not change.
Three qualities, or a size limit
- Print quality (300 DPI): files going to a print shop or photo printing. The least shrinking, the highest quality.
- Balanced (150 DPI): screen, email and office printers. The recommended setting for most documents.
- Smallest (100 DPI): forms with an upload limit. Easy to read on screen; a large print may look soft.
- Size limit: pick a limit such as “max. 2 MB” and the tool lowers the quality step by step, keeping the highest quality that fits. If nothing fits, you get the smallest version it can make and the reason why.
When a PDF barely shrinks
A PDF with lots of text and few images (a contract saved from Word, say) is small already; its weight is the fonts, and they stay as they are. Black-and-white scans are often stored in very efficient formats (JBIG2, CCITT) already. CMYK and spot-colour images are left alone so print colours do not shift. The result card says which images were left and why, and the tool never hands back a file larger than the original.
Signed PDFs
Compressing a PDF that carries a digital signature means writing it again, and the signature stops being valid. The tool notices the signature and warns you. Send the original wherever the signature has to hold.
Nothing is uploaded
The PDF opens in this tab and the images are recompressed with your browser’s own decoder. There is no server that accepts files. To join several PDFs into one, use merge PDF; to see the print resolution of the images, use the PDF DPI checker.
How to compress a PDF
Step 1: Drop the PDF
Drag it into the box above or click to choose it. Pick several PDFs and they are all compressed with the same setting and come back as one ZIP.
Step 2: Choose a quality or a limit
If you know what the file is for, pick the quality. If a form says “max. 1 MB”, choose “To a size limit” and tick 1 MB.
Step 3: Compress and download
Press the button. The result card shows the new size, how many images were reduced and why any were left alone.
Frequently Asked Questions
Does compressing a PDF lower its quality?
Only in the images, and only as far as you choose. Because each image is sized for where it sits on the page, the Balanced setting shows no difference on screen or on an office printer. Text and drawings do not change at all.
How do I get a PDF under 1 MB?
Choose “To a size limit” and tick 1 MB. The tool reduces the images step by step and gives you the best quality that fits. If most of the document’s weight is fonts, the limit may not be reachable; you then see the smallest size it got to, and why.
Does the text stay selectable?
Yes. Pages are not turned into pictures; text, fonts, links and form fields stay as they are.
Can an encrypted PDF be compressed?
A PDF with an open password, or one protected against changes, cannot be written again. Remove the protection in the program that made the document and try again.
Why do some PDFs not shrink at all?
A PDF without images, or with images that are already compressed well, has nothing left to shrink. The tool never produces a bigger file; in that case your original stays as it was.
Is my file uploaded anywhere?
No. All the work happens in your browser; the file is not sent to any server.
Related Tools
- PDF DPI Checker: Check the DPI of a PDFSee the effective DPI of every image in a PDF, and where the low-resolution ones sit on the page.
- Free CV Maker with Cover Letter — No Sign-UpBuild a CV and a cover letter in German, Turkish or international format and download the PDF. No account, no card, and nothing you type leaves your device.
- Word (.docx) to PDF ConverterTurn Word documents into PDF in your browser, with zero data leaving your device.
- PDF to Word (.docx) ConverterTurn the text in your PDF into an editable Word document.
- PDF Merger (Combine PDFs)Combine several PDFs into a single document, in the order you set.
- PDF Page Splitter / ExtractorPick pages by clicking their thumbnails, or type a range like 1-3, 5.