Frequently Asked Questions
Is everything really processed in my browser?
Yes. Every tool on OhMyPDF runs as JavaScript inside your browser tab. Your PDF is read into memory, edited, and offered as a download — without ever traveling to a server.
Do I need to sign up?
No account is needed. Just open a tool and drop a file.
Is it free?
Yes — completely free. The site is supported by ads.
Can I use it offline?
Yes. After the page is loaded once, the tools keep working without a network connection. The browser caches the JavaScript and HTML.
What is the maximum file size?
Each individual PDF or image is capped at 100 MB. Multi-file inputs (Merge, Images to PDF) accept up to 50 files. Browser memory is the real bottleneck — desktop browsers handle the limits more comfortably than mobile.
Why does my compressed PDF barely shrink?
Browser-side compression cannot re-encode embedded images the way a desktop tool like Ghostscript can. Realistic savings are 5–30%; sometimes the file does not shrink at all. We are upfront about this in the Compress PDF tool.
Can I integrate the tools into my own product?
The libraries used (pdf-lib, pdfjs-dist, jszip, file-saver) are all open source. Each tool wrapper here is small enough to copy.
How are sensitive documents handled?
PDFs you drop in are processed locally — see the Privacy Policy. Even so, never upload PDFs containing secrets to any third-party site you do not control.
Why do I see ads?
Ads cover the running cost of the site (domain, hosting, time). Ads are clearly labeled and never block the tools.