Question 1

Do these PDF tools upload my documents anywhere?

Accepted Answer

No, and that is the single design decision behind all of them. Each tool downloads a compact processing engine into your browser once, then reads, transforms and writes the document entirely in memory on your own machine. In practice that makes every tool here equally appropriate for a confidential contract, a payslip, a medical form or a bundle of scanned evidence, because at no point does the document exist anywhere except the device you opened it from.

Question 2

Do I need an account or to install anything?

Accepted Answer

No. There is no account to create, no email address to hand over and nothing to install. The processing engine ships as part of each page, which is why there is no software to keep updating and why the tools behave the same way on a laptop and on a phone. Chrome, Edge, Firefox and Safari are all supported.

Question 3

Why are browser-based PDF tools faster?

Accepted Answer

There is no upload phase and no queue, so a conversion begins immediately and the limiting factor is your own processor rather than your connection. A job that would sit in a progress bar for minutes on a typical upload-based service finishes as fast as your machine allows, and it keeps working even if your connection drops partway through.

Question 4

Which PDF tool should I use?

Accepted Answer

Compress when a document is too heavy for a destination, merge when several files need to become one, and split when a document holds far more than the part you need. Because each tool is deliberately narrow and leaves the original untouched, you can also chain them: extract the two pages you actually need from a long report, then compress that short extract.

Question 5

Why are my PDF files so large?

Accepted Answer

Almost always because of images. Text, fonts and vector graphics are already stored efficiently, so a single page scanned at high resolution can weigh several hundred kilobytes on its own and a report built from such scans can reach fifty megabytes while containing nothing that genuinely needs that much data. The waste is nearly always in the pictures, which is exactly what compression targets.

Question 6

How do I stop a PDF losing quality when I compress it?

Accepted Answer

Aim for the smallest file that still reads correctly rather than the lowest setting available. Artefacts appear first in small text and fine detail, long before the file becomes noticeably smaller, so inspect the result at full size before you send it. Resizing oversized source images before converting also achieves more than any quality setting and leaves the text completely untouched.

Question 7

Does merging or splitting keep my document usable?

Accepted Answer

Both copy page content exactly, so text, images, vector graphics and form fields survive intact, which is what makes them dependable for legal, financial and official work. The catch is document-level features: bookmarks from separate files are not woven into one table of contents, internal links to pages you removed stop resolving, and digital signatures may not validate once the file has been rewritten.

Question 8

Why do the page numbers in my PDF not match the printed numbers?

Accepted Answer

A PDF counts pages from the start of the file rather than from the first page bearing a printed number, so a document with a cover sheet and a contents page is offset from what the reader sees. This is the detail that catches people out when extracting a range, and the visual page overview is the reliable way to confirm exactly what you are selecting.

Question 9

Can I chain these tools together?

Accepted Answer

Yes, and it is usually the better order of operations. Extracting the pages you need first and then compressing that short extract gives a much better result than compressing a long document and trimming it afterwards, because each step is easy to verify on its own and the engine does not spend effort on pages you were going to discard. Every tool leaves the source file unchanged, so you can run them repeatedly.

Question 10

Is there a limit on how large a PDF I can work with?

Accepted Answer

The limit is your device's free memory rather than the service. Processing needs roughly two to three times the size of the file, because the original, the result and the intermediate data all exist at the same time. On a recent computer this is rarely a problem; on an older phone, or with many heavy tabs open, a large file may be slow or fail, and closing other tabs is often the whole fix.

Question 11

Can I use these tools offline?

Accepted Answer

Yes. Once a page has loaded, everything runs locally on your own device, so the tools keep working with no connection at all. Closing the tab discards everything, and there is no account, no payment method on file and nothing retained afterwards.

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PDF Tools: Frequently Asked Questions