PDF Tools
About PDF
PDF (Portable Document Format) was created by Adobe in 1993 and became an open ISO standard in 2008. It is designed to present documents — text, images, vector graphics, fonts, and layout — consistently across every device, operating system, and printer, regardless of the software used to create them.
PDF is the universal standard for sharing documents that must look exactly the same everywhere: contracts, forms, invoices, academic papers, and print-ready artwork. Nearly every computer and smartphone can open a PDF without installing special software.
How PDF Files Work
A PDF file is a structured container that bundles everything needed to render a document: compressed page streams, embedded fonts, image data, vector paths, metadata, and an index (cross-reference table) that maps object positions for fast random access. Pages are rendered by interpreting a PostScript-like language that positions each element precisely.
Because fonts and layout information are embedded, a PDF looks the same whether opened on Windows, macOS, Linux, iOS, or Android — even if the fonts used in the document are not installed on the viewing device.
Working with PDFs in the Browser
Modern browsers include a built-in PDF renderer (based on Mozilla's pdf.js), which means PDF files can be read, processed, and manipulated entirely in JavaScript without any server-side component. The tools on this page use this capability to handle your files locally — nothing is ever uploaded.
The key JavaScript libraries used are:
- pdf.js — Mozilla's open-source PDF rendering engine; used for reading pages, extracting text, and rendering page thumbnails
- pdf-lib — A full PDF manipulation library; used for merging, splitting, rotating pages, and editing metadata
- jsPDF — A PDF generation library; used for creating new PDFs from images or canvas elements
PDF Versions and Compatibility
PDFs are versioned, from PDF 1.0 (1993) to PDF 2.0 (2017). Most tools in the wild produce PDF 1.4 to PDF 1.7 files. Key features introduced over time include:
| Version | Notable Features |
|---|---|
| PDF 1.3 | 128-bit encryption, embedded ICC colour profiles |
| PDF 1.4 | Transparency, JBIG2 compression |
| PDF 1.5 | Cross-reference streams, object streams, JPEG2000 |
| PDF 1.6 | 256-bit AES encryption |
| PDF 1.7 | Adobe extensions (became ISO 32000-1) |
| PDF 2.0 | ISO 32000-2; improved encryption, digital signatures |
Common PDF Tasks
- Compressing a PDF — Large PDFs are often caused by high-resolution embedded images. Compression tools re-encode those images at lower resolution or quality, which can dramatically reduce file size with little visible quality loss for screen viewing.
- Merging PDFs — Combining multiple PDF files into one is common for assembling reports, combining scanned pages, or consolidating receipts. The page order can be controlled before generating the merged file.
- Splitting PDFs — Extracting a page range from a large PDF creates a focused document without the surrounding content. Useful for sharing one chapter from a large report.
- Rotating pages — Scanned documents often have pages in the wrong orientation. Rotating pages corrects orientation without re-scanning.
- Converting PDF to images — Rendering PDF pages as JPEG or PNG images is useful for creating thumbnails, sharing non-editable previews, or embedding PDF content in web pages.
Frequently Asked Questions
- Are my PDF files sent to a server?
- No. All tools on this page run entirely in your browser using JavaScript. Your files are processed locally in memory and are never transmitted to any server.
- Can I process password-protected PDFs?
- PDFs with owner passwords (restricting editing, printing, or copying) can still be opened without a password in most cases. PDFs with user passwords (requiring a password to open) cannot be processed without first removing the password protection.
- Why are some PDFs larger than expected?
- Large PDFs are usually caused by high-resolution embedded images, unsubsetted fonts (where the entire font is embedded rather than just the characters used), or large embedded media. The compression tools can help reduce image-heavy PDFs significantly.
- What is a PDF/A file?
- PDF/A is an ISO standard subset of PDF designed for long-term archiving. It embeds all fonts, forbids encryption and external references, and prohibits features that could change the document's appearance over time. Government and legal archives often require PDF/A format.