Compress PDF to 400 KB

Upload your document, pick a compression level, and get a smaller file.

Drop your file here to start

Supports PDF

Size up to 100 MB

Supports PDF

Size up to 100 MB

How to compress PDF to 400 KB

Follow three quick steps to create a smaller file for sharing or storage.

1.🚀
Choose your PDF
Select the PDF you want to make smaller from your device.
2.⚡
Choose a level
Check the estimated size for each level and pick the one that gets under 400 KB.
3.✅
Download your file
Save the compact PDF to your device when processing is complete.

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A simple way to reduce PDF to 400 KB

📝

See the size first

Each level shows an estimated file size before you compress, so you know whether the result will clear a 400 KB upload limit.

⚡

Clear document quality

Compression balances size reduction with legibility, so text and page elements stay clear in the downloaded document.

🎨

Faster sharing

A compact document is easier to attach to emails, submit through online forms, and share through messaging services.

🔄

Browser-based access

Use the online workflow without installing software or creating an account.

🖋️

Simple file handling

You can compress PDF to 400 KB online free of charge: upload one file, pick a level, and save the smaller PDF to your device.

📋

Ready for storage

The smaller output uses less storage space and is convenient for keeping records, forms, reports, or study materials.

Frequently asked questions

Why is the file still over 400 KB?

Usually because of images. Scans and photos take up most of a PDF's size, so a light level may not remove enough. Check the estimate at High, which gives the smallest result. If the file is still over, compress the result again at High, or remove pages you don't need.

Will photos keep a PDF above 400 KB?

They can. Large, high-resolution photos often make up most of the file size, so a photo-heavy PDF may stay above 400 KB at Low or Medium. Choose High and check the estimate. If several photos still keep it over, consider removing the ones the document doesn't need.

Do the pictures have to shrink before a text-heavy file can clear 400 KB?

Not usually. Text takes up very little space, so a text-heavy file often clears 400 KB at Low or Medium with its pictures barely touched. If it doesn't, the pictures are what's holding it back: choose High, which compresses them more, and check the estimate.

Does reducing a PDF to 400 KB affect readability?

Text usually stays readable at every level, while images may lose fine detail at High. For documents that are mostly text, Low or Medium is often enough to compress PDF to 400 KB without losing quality. For scans and photos, check the downloaded file before you send it.

Do I need to install software to compress a PDF?

No. PDFFly works in your browser on Windows, Mac, Linux, Android, and iPhone. Upload the PDF, choose a compression level, and download the result. There is no software to install and no account to create, and the compressed file is saved straight to your device.