What is a PDF file?
A PDF looks the same to everyone who opens it, on any device, with the fonts, images and layout locked in place. That is why forms, invoices, contracts and anything meant to be printed get sent as PDFs. You can convert PDF files here, both into the format and out of it.
Specification
| Full name | Portable Document Format |
|---|---|
| Extensions | |
| Media type | application/pdf |
| Compression | Lossy or lossless, depending on the mode |
| Transparency | — |
| Animation | — |
| Multiple pages | Supported |
| Colour depth | RGB, CMYK, greyscale and spot colour with ICC profiles |
| Size limits | 381 x 381 km page size limit, 5 GB practical file ceiling |
| Introduced | 1993 |
| Developed by | Adobe, now ISO 32000 |
| Standard | Open |
| Browser support | Every browser, including older ones |
What PDF is used for
- Contracts, invoices and anything that must print exactly as designed
- Academic papers, manuals and long-form documents shared for reading
- Print production, where PDF/X is the delivery standard
- Scanned paper archives with an OCR text layer behind the image
Strengths and limitations
What PDF does well
- Layout, fonts and colour are fixed, so the file looks the same everywhere
- Every browser and operating system opens it without extra software
- Handles text, images, forms and digital signatures in one file
Where PDF falls short
- Editing an existing PDF is awkward because it stores drawing commands, not structure
- Reflowing text for a small screen works poorly and often fails entirely
- Extracting reliable text from a scan requires OCR, which introduces errors
Convert PDF to
Every target this format can be written out as, each on its own page.
Convert to PDF
Everything that can be turned into a PDF file.
Tools that accept PDF
Questions about PDF
What is a .pdf file?
A PDF looks the same to everyone who opens it, on any device, with the fonts, images and layout locked in place. The extension .pdf identifies it, and its media type is application/pdf.
How do I open a PDF file?
Any current browser will open it directly, so dragging the file into a tab is usually enough. Most operating systems also preview it without extra software.
Is PDF lossy or lossless?
Lossy or lossless, depending on the mode. Check which mode a particular file used before assuming anything about its quality.
What is PDF good for?
Layout, fonts and colour are fixed, so the file looks the same everywhere. Every browser and operating system opens it without extra software. Handles text, images, forms and digital signatures in one file. In practice that makes it a good fit for contracts, invoices and anything that must print exactly as designed, and Academic papers, manuals and long-form documents shared for reading.
What are the drawbacks of PDF?
Editing an existing PDF is awkward because it stores drawing commands, not structure. Reflowing text for a small screen works poorly and often fails entirely. Extracting reliable text from a scan requires OCR, which introduces errors.