About Compress Multiple PDFs
Compress Multiple PDFs shrinks a whole stack of PDF files in one go. Drop in every file at once, choose a compression level, and download all the smaller copies in a single ZIP, each one keeping its original file name with a -compressed suffix.
People look for a batch PDF compressor when one file is not the problem: an accountant sending a month of scanned receipts, a teacher collecting forty homework scans, an HR team archiving hundreds of signed contracts, or a student uploading a portfolio to a portal that caps every file at 2 MB. Compressing those one by one wastes an afternoon.
Everything runs inside your browser. The files never reach a server, there is no queue, no daily quota and no cap on how many PDFs you add, which matters when the batch contains payslips, ID scans or client records.
How to use Compress Multiple PDFs
- Click Choose PDF files and select all the PDFs you want to compress, or drag a whole selection from your file manager onto the page.
- Add more files at any time with the Add more PDFs box. Remove any file with its X button.
- Pick one level for the batch: Light for print, Balanced for email and portals, Strong for the smallest files.
- Tick Maximum compression only if the batch is mostly scans and the standard levels are not enough.
- Click Compress, wait for the progress bar, then download the ZIP or save files one by one from the list.
One click, many files
The same settings apply to every PDF, so a batch of 50 takes the effort of one.
One ZIP download
All compressed files arrive in a single ZIP, with each file also downloadable on its own.
Never bigger
If a file can't be made smaller, its original goes into the ZIP instead of a heavier copy.
No upload, no cap
Files stay on your device. There is no file count limit and no per-day quota.
How batch PDF compression works, and how to get the best result
The tool processes your PDFs one after another, not all at once. Each file is read, its embedded photos and scans are re-encoded at the level you chose, and the result is saved before the next file starts. Working sequentially keeps memory use flat, so a laptop can get through a batch of several hundred megabytes without slowing to a crawl. The progress bar counts across the whole batch.
Text and vector graphics are never touched by the standard levels. Light keeps images up to 2400 pixels on the long side at 82 percent JPEG quality, Balanced keeps 1600 pixels at 68 percent, and Strong keeps 1100 pixels at 50 percent. An image is only replaced when the new version saves at least 5 percent. That is why a batch of mixed files gives mixed results: a photo-heavy brochure might drop by 90 percent while a text-only invoice barely changes.
Sort the batch by type when the results matter. Scanned documents, where every page is one big picture, respond best to Maximum compression, which renders each page as a JPEG. Exported reports and contracts with selectable text should stay on the standard levels so the text remains searchable. Running two smaller batches with different settings often beats one batch with a compromise setting.
If a file in the batch is password protected or damaged, it is flagged in the list before you start, and any file that fails during compression is skipped and named in the result. The rest of the batch still finishes, so one bad file never costs you the other forty-nine. Unlock protected files with Unlock PDF and add them in a second run.
Compress each file once, at the end of your workflow. Running a batch that was already compressed through the tool again adds blur and saves little. If you also need the files merged into one document, merge first and compress the merged file, because shared fonts and images are then stored only once.
Tips for better results
- Start the batch on Balanced. Re-run only the files that are still too large on Strong.
- Keep scans and text documents in separate batches so each gets the right setting.
- Remove password protection before adding files, or they will be flagged and skipped.
- For very large batches on a phone, split them into groups of 20 to 30 files.
- Keep the originals until you have checked the compressed copies.
Questions and answers
How many PDFs can I compress at once?
There is no fixed limit. The practical limit is your device's memory, and because files are processed one at a time, most laptops handle hundreds of files in a batch.
Do I get one ZIP or separate files?
Both. The Download all (ZIP) button saves one ZIP, and the list below it lets you save any single compressed file.
Are my files uploaded to a server?
No. Compression runs entirely in your browser, so the PDFs never leave your device.
What happens if one file can't be compressed?
It is skipped and named in the result, and the rest of the batch still completes. Files that are already well optimized are kept as they were.
Can I use different levels for different files?
One level applies to the whole batch. Run a second batch for files that need a different setting.
Does batch compression blur the text?
No. The standard levels only recompress images. Only the Maximum compression option turns pages into pictures.
Is this different from Compress PDF?
It is the same engine. Compress PDF also accepts several files, and this page explains the batch workflow in more detail.