How to Work with PDFs in Your Browser
By Tools Star Hub Editorial Team · Published · Updated
Browser PDF tools on this site open the file in the tab. A PDF must be 20 MB or smaller. Merge combines up to 10 PDFs and 80 pages in the order you add them, and it copies pages without resizing them. Light and balanced compression keep text and vectors. Strong compression renders each page as a JPEG, replaces selectable text, and handles up to 40 pages. The other rewrite presets handle up to 80 pages.
Uploading a contract or a statement to an unknown server is a separate decision from shrinking or joining the file. Doing the work in the browser keeps the bytes on the machine you are using. The limits are there so the tab stays responsive. A tool that refuses a 90-page merge is telling you to split the job, not guessing at the content.
What does every PDF tool check first?
The file should be a PDF, it should not be empty, and it should be 20 MB or smaller. The bytes are also checked for a PDF signature. A damaged file can fail with a message that it could not be read. A password-protected file fails until you unlock it. These tools do not ask for the password.
Page counts matter after the file opens. The page counter reads the stored pages, including blanks. Rendering tools, including PDF to JPG and strong compression, stop at 40 pages. Plan a split before you send a longer file to those tools.
How do merge and split behave?
Merge needs at least two PDFs and accepts up to 10. The combined page count must be 80 or fewer. Pages are copied in the order of the files and appended. They are not scaled to a single paper size. A letter page and a smaller page stay their own sizes.
One file does not need merging, and the merge tool says so. Split takes one PDF and a page selection. Use the page count first if you are not sure which numbers to type. A reversed range is rejected.
What is the difference between compression levels?
Low compression rewrites the PDF with object streams. Page content stays as vectors and text, and the size often drops only a little. Balanced copies pages into a new PDF and drops unused objects. Text and vectors are kept. Compression is not guaranteed at either of those levels.
Strong compression renders each page to a JPEG and rebuilds the file. Selectable text and vector drawings are replaced by images. It handles up to 40 pages. Use it when a smaller file matters more than selecting text later. Light and balanced stop at 80 pages.
How to work with PDFs in the browser
- Stay within 20 MB. Every PDF tool here rejects a larger file. Compress or split elsewhere only if you accept that other tool’s handling of the file.
- Count pages before a merge or a render. Merge allows 80 combined pages. Strong compression and PDF to JPG allow 40 pages.
- Pick a compression level on purpose. Light and balanced keep text selectable. Strong replaces pages with JPEG images.
- Check the downloaded file. Open it and confirm the page order, the text selection, and the page count. The original file is not overwritten in place by these tools.
Example
Two short PDFs
Merge copies every page from the first file, then every page from the second. Two 3-page files become a 6-page PDF if both open. The pages keep the sizes they already had.
Strong compression
A file of 40 pages or fewer can be rebuilt from JPEG page images. The text will not select afterward. A 41-page file is over that cap and needs a different preset or a split.
Common mistakes
Strong compression removes selectable text
The page becomes a picture. Use light or balanced when you still need to search or copy the words.
Merge does not resize pages
Mixed page sizes stay mixed. The tool copies pages in order. It does not scale them onto one sheet size.
FAQ
- How large can a PDF be?
- 20 MB. Larger files are rejected so the browser tab stays usable.
- How many PDFs can I merge?
- Up to 10, with 80 pages combined. You need at least two files. Pages are copied in file order and are not resized.
- Which compression keeps the text selectable?
- Light and balanced. They keep vectors and text. Strong compression renders pages as JPEG images and handles up to 40 pages.
- Can these tools open a password-protected PDF?
- No. Unlock the file first. The tools do not ask for the password.
- Is the PDF uploaded?
- No. Merge, split, count, and compress run in the browser.
To shrink a PDF with a preset you can see, use the PDF Compressor. Light and balanced keep text. Strong compression rasterizes pages.
Counting pages before a merge is covered in How to count the pages in a PDF.
Image files have a different kind of compression. See How to compress an image without losing quality.