Compress PDF
Add PDFs, choose how small, and compress. Your files never leave your device.
Only images are made smaller. Text stays selectable. If a file can’t get smaller, the original is kept.
This is a Premium feature (¥980/month). Free: up to 3 files at a time. Learn more
PremiumUnlimited files at once, Make photos and images grayscale. The same Premium also unlocks extra features in our other tools. Learn more
Install Kitbench as an app to open PDFs and images with right-click
PDFs are compressed in this page only. Nothing is uploaded. Images inside the PDF are made smaller; text and drawings are kept as they are. PDF processing uses pdf-lib (MIT License).
How to use
- 1. Add PDFsDrop them on the box or click to choose.
- 2. Choose how smallPick Light, Recommended or Strong. To meet an upload limit, tick “Make it under” and enter the size in MB.
- 3. CompressClick “Compress PDF”. One file downloads right away; with several files, download each or all as a ZIP.
Which level should I pick?
| Level | Images become | Good for |
|---|---|---|
| Light | Up to 2400 px on the long side, high quality | Printing, documents with fine photos |
| Recommended | Up to 1600 px, standard quality | Email attachments, sharing, most uses |
| Strong | Up to 1100 px, lower quality | Upload forms with strict limits, viewing on screen |
Common size limits
| Where | What to do |
|---|---|
| Email attachments | Many mail services limit the total size of attachments. The target size applies to each file, so when attaching several, make each one smaller so the total fits |
| Online forms and job applications | Check the limit shown on the form and enter it in “Make it under” |
Private by design
Your PDFs are never sent to a server. They are compressed inside your browser, so documents with business or personal information stay on your device.
PDF reading and writing uses pdf-lib, an open-source library under the MIT License.
Sources: pdf-lib (MIT License)
FAQ
Who is this tool for?
It suits people who need a smaller PDF: job applicants and anyone filling in an online form with a size limit, office and sales staff emailing quotes or reports full of photos, people who want scanned documents to take up less space in cloud storage or on their phone, and anyone shrinking private files such as ID scans or contracts (nothing is uploaded).
When is it most useful?
For example, when an upload form says the file is too large, when an attachment is too big to email, when a PDF made from phone photos is heavy, or when you want a photo-heavy catalog or deck to open quickly for the people you send it to.
What do I gain from using it?
You can set a target such as “under 1 MB” instead of trying different settings over and over. The before and after sizes and the percentage saved are shown, so you know right away whether the file fits the limit. Text stays selectable, so the recipient can still search and copy it.
Are my files uploaded?
No. Compression happens in your browser, so contracts, ID scans and other private documents never leave your device. If you use Premium, the page checks once a day that your subscription is active; only your Premium key is sent for that, never your PDFs.
Can I make it under a specific size?
Yes. Enter a number in the “Make it under” box (the checkbox ticks itself) and the tool compresses step by step until the file fits. If it can’t get that small, it keeps the smallest result and tells you. For less than 1 MB, use a decimal such as 0.5 (about 500 KB); a number a little below the limit is safer. The target applies to each file separately, so if a form limits the total, aim lower for each file.
Will the text still be selectable?
Yes. Only the images inside the PDF are re-saved at a smaller size. Text and vector drawings are not touched, so you can still select and search the text.
Why didn’t my PDF get smaller?
PDFs that are mostly text are already small. Some image types are also left unchanged, such as CMYK print images, black-and-white (1-bit) scans and JPEG 2000, as are very small images like icons and lines. When a file can’t get smaller, the original is kept as it is, with its original name.
What about scanned PDFs?
In a scanned PDF, the text is part of the image too. With Strong or a small target size, small text can get blurry, so open the file and check it is readable before you send it.
What’s the difference between Light, Recommended and Strong?
They set how far the images inside the PDF are scaled down. The longest side of each image is limited to 2400 px for Light, 1600 px for Recommended and 1100 px for Strong, with image quality lowered step by step. With a target size, the tool can go beyond Strong (850, 650 and 480 px) until the file fits. If you’re unsure, start with Recommended.
How many files can I compress at once?
Up to 3 files at a time for free. If you add 4 or more and press Compress, you’ll see a notice, so remove some first. With Premium you can compress more than 3 PDFs in one go. With many files, it can take longer depending on your device.
Can I compress password-protected PDFs?
No. Password-protected PDFs can’t be opened here. PDFs with editing or printing restrictions (encryption) may not open either, even if they don’t ask for a password.
Does it work on a phone?
Yes. On a narrow screen the settings and results are stacked from top to bottom. When you compress a single PDF and it gets smaller, it downloads right away.
Is there a file size limit?
There is no set limit. Because the PDF is processed on your own device, very large or image-heavy files can take longer depending on your computer or phone.
How do I save several compressed files?
Use each file’s Download button, or “Download all (ZIP)” to get them in one ZIP file. Files that got smaller have “_compressed” added to the original name (files that couldn’t get smaller keep their name). Your original files are not changed.
What does “Remove document info” do?
When ticked, the document information stored in the PDF, such as the title and author, is removed before saving. Use it when you don’t want to share details like who made the file. The page content stays the same.
What does “Make photos and images grayscale” do?
This is a Premium feature. Photos and other images inside the PDF are turned gray before they are shrunk. The color of text and lines doesn’t change, and very small images, image types we leave unchanged, and images that didn’t get smaller stay in color.
Premium
One Premium. Every upgrade, as much as you like.
- Unlimited files at once
- Make photos and images grayscale
- All paid features in every extension
- Premium features in Kitbench web tools
- Extensions we release later are included
- Monthly¥980/month
- Yearly¥9,800/year (about ¥817/month)
- Lifetime¥14,800 once
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