“We noticed you may be using an ad blocker. SEO Site Checker relies on ads to keep our SEO tools free. Please consider disabling your ad blocker to support us - thank you!”“We noticed you may be using an ad blocker. SEO Site Checker relies on ads to keep our SEO tools free. Please consider disabling your ad blocker to support us - thank you!”
Upload a PDF, pick a quality level and download a smaller copy saved for fast web view. Free, no account, no watermark.
Max file size: 60 MBGet 500 MB per upload, freeSign up free
Uploading your PDF…
0%
How to Optimize a PDF
Quick answer: To optimize PDF files online for free, upload one PDF, pick a level and download. This free pdf optimizer re-encodes the images when that makes the file smaller, then always saves a linearized, web ready PDF (Fast Web View), so a viewer can draw page one before the rest arrives. Try it with your own file.
Upload. One PDF per run, 60 MB for guests, 500 MB with an account.
Choose Optimization Quality. E-book is preselected.
Select Optimize PDF and download.
A protected file needs its password in the uploader, or the tool points you to Unlock PDF.
Tip: To optimize PDF for email and cut PDF file size, run Screen on your original, not an optimized copy. Open it.
Which Quality Level to Pick
The levels are Ghostscript presets, listed in the Ghostscript pdfwrite documentation. Our test file: six 2400 by 1600 photos, 3,936,595 bytes.
Level
Target resolution
Use it for
Our test result
Screen (72 dpi, smallest file)
72 dpi
Email attachment
150,200 bytes
E-book (150 dpi, balanced, the default)
150 dpi
Website upload
542,664 bytes
Printer (300 dpi, high quality)
300 dpi
Office printing
3,938,262 bytes
Prepress (300 dpi, color-accurate)
300 dpi
Print proofs
3,938,262 bytes
Screen and E-book downsample images with lossy compression, so check the result. Printer and Prepress returned 3,938,262 bytes, slightly more than we uploaded. Our photos are 336 ppi and the output came out no smaller, so the tool kept the original content and added Fast Web View. Savings come only from images; test your own.
Optimize PDF vs PDF Compressor
Both use Ghostscript presets, within 1 percent. The PDF Compressor gave 149,635 and 542,095 bytes on the same file, against our 150,200 and 542,664. Part of that small gap is likely linearization with qpdf (see the qpdf documentation on linearization): pdfinfo reports Optimized: yes for our output, no for the compressor. Pick this tool to optimize PDF for web use, the compressor when bytes are all that matter.
What It Keeps and What It Changes
Text, bookmarks and links survived. Re-encoded output is PDF 1.4, where our original was 1.7 (PDF versions).
Fillable fields were flattened in our test, so keep an original of any form. The password is dropped; add it back with Lock PDF. A scanned document stays unsearchable; try OCR PDF.
A small text-only PDF can grow. If the re-encode would be larger, we keep your original content and add Fast Web View: 6,261 bytes became 7,806 at every level.
What Happens to Your File
We delete your upload when the job ends. The result is removed after about two hours.
Frequently Asked Questions (FAQs) is a list of common questions and answers provided to quickly address common concerns or inquiries.
How do I optimize a PDF for free?
Upload one PDF to the tool above, leave Optimization Quality on E-book or choose another level, select Optimize PDF and download. It is free, adds no watermark and needs no account up to 60 MB.
What is the difference between optimizing and compressing a PDF?
Optimizing uses similar Ghostscript presets, adds Fast Web View and offers a fourth level, Prepress. On our 3,936,595 byte file we got 150,200 and 542,664 bytes, within 1 percent of the compressor. Use the compressor when size is all that matters, this tool when the file will be viewed online.
What does Fast Web View mean?
The file is linearized with qpdf, so a viewer that supports progressive loading can show page one before the whole file has downloaded. pdfinfo reports Optimized: yes. It helps long files on a website page.
Will optimizing reduce the quality of my PDF?
Images can lose detail at Screen and E-book, which resample to 72 and 150 dpi. Text, links and bookmarks stay. At Printer and Prepress our photos came out no smaller, so the original content was kept.
Why did my optimized PDF come out the same size or larger?
A text-only or already compact PDF has little to remove. When the re-encode would be bigger, we keep your original content and add Fast Web View data. Our 10 page text PDF went from 6,261 to 7,806 bytes; a 300 page one shrank from 189,858 to 155,577.
Can I optimize a password protected or fillable PDF?
A protected PDF works once you enter its password in the uploader, but the output has no password, so run Lock PDF afterward. Without it the tool refuses and points to Unlock PDF. Fillable fields were flattened in our test, so keep a copy.
Is there a file size limit and what happens to my file?
Guests can upload 60 MB and a free account 500 MB, one file per run. The upload is deleted when the job ends. The result is deleted after about two hours, and anyone with the link, a random address that is not listed anywhere, can download it until then.
We use cookies to personalize content and ads, to provide social media features and to analyze our traffic. You consent to our cookies if you continue to use our website.
Install SEO Site CheckerFree SEO tools - always in your pocket.
