Format guide

PDF vs PNG: When to Use Each Format

Both formats store visual information, but they do it in fundamentally different ways. PDF keeps the structure — text, vectors, fonts — so you can scale a page to any size without losing sharpness. PNG freezes a page into a fixed grid of pixels: what you see is exactly what you get, at exactly one resolution. Picking the right format comes down to what you plan to do with the file next.

Published August 17, 2026

What is a PDF?

PDF (Portable Document Format) is a container that describes a page as a set of instructions: place this glyph at these coordinates, draw that vector path with this fill, embed this font subset. A viewer follows those instructions to paint the page, so the output looks the same on every screen and every printer regardless of the software or operating system.

Because the structure is preserved, text inside a PDF is selectable and searchable. A two-page contract stays as two logical pages, footnotes link to their targets, and a 50-page report can carry bookmarks. PDFs can also embed images, form fields, and even JavaScript — the format is a full document model, not just a picture of one.

What is a PNG?

PNG (Portable Network Graphics) is a raster image format. It stores a rectangular grid of pixels — each with a colour value and, optionally, a transparency value. A 1920 × 1080 PNG contains exactly 2,073,600 pixels, and the file is done: there are no fonts to load, no vectors to trace, no pages to paginate.

PNG uses lossless compression, so the image you open is bit-for-bit identical to the one that was saved. That makes it ideal for screenshots, diagrams, UI elements, and anything with sharp edges or flat colours. It also supports full alpha transparency, which is why logos and icons exported for the web are almost always PNGs.

Key differences at a glance

Feature	PDF	PNG
Content model	Vector + raster + text	Raster only (pixel grid)
Scaling	Lossless at any zoom	Degrades when enlarged
Text	Selectable and searchable	Baked into pixels
Transparency	White background by default	Full alpha channel
Multiple pages	Yes	No — one image per file
Editability	Editable with PDF editors	Editable with image editors
Compression	Mixed (per object)	Lossless (deflate)
Typical file size	Smaller for text-heavy docs	Larger for full-page images
Web embedding	Requires a viewer or iframe	Native <img> tag

Quality comparison

Quality is not really a property of the format — it depends on what is inside. A PDF holding a scan at 100 DPI looks just as soft as a PNG of that scan at 100 DPI. The difference shows up when you scale: the PDF can re-rasterise from vector data, so zooming in on a text paragraph stays sharp. The PNG has no vectors to re-draw, so zooming in just makes the existing pixels larger.

For photos, the gap is smaller. Both formats can hold photographic content, but a PDF usually JPEG-compresses the embedded image anyway, so extracting it to PNG does not magically add detail. The PNG version will be lossless going forward — no further degradation on save — but the quality ceiling was set when the photo entered the PDF.

File size

A text-heavy PDF is almost always smaller than its PNG equivalent, because the PDF stores glyph coordinates and a font subset rather than millions of coloured pixels. A single-page letter-size document at 300 DPI becomes a PNG of roughly 2550 × 3300 pixels — easily 5-10 MB depending on content. The same page as a PDF might be 50-200 KB.

The equation flips for image-heavy documents. A PDF that embeds a dozen high-res photos can be larger than the PNG of one page, because the PDF carries all the embedded data. In general: if the content is mostly text and vectors, PDF wins on size; if you only need one page as a flat image, PNG is comparable or smaller.

When to use PDF

Documents meant to be read or printed. Contracts, invoices, reports, resumes — anything where you need consistent layout across devices and the recipient should be able to search or copy text.
Multi-page content. A portfolio, a slide export, or an e-book stays as one file with its own pagination and bookmarks.
Archiving. PDF/A is an ISO standard specifically for long-term preservation of electronic documents.
Forms and signatures. PDF supports interactive form fields, annotations, and digital signatures natively.

When to use PNG

Embedding a page in a website, slide, or chat. A PNG drops straight into an <img> tag, a Google Slide, or a Slack message — no viewer needed.
Screenshots and diagrams. Flat colours and sharp edges compress well in PNG without the ringing artifacts JPEG would add.
Transparent overlays. Logos, icons, and cutouts that need to sit on top of another background rely on the alpha channel only PNG (and WebP) provide.
Image editing workflows. Crop a chart out of a report, annotate a scan, or feed a page into an OCR pipeline — image editors expect raster input.

Converting between PDF and PNG

Going from PDF to PNG means rasterising: the converter reads the page instructions and paints them onto a pixel grid at the resolution you choose. Higher DPI means more pixels, sharper text, and a larger file. 150 DPI is enough for on-screen use; 300 DPI is standard for print.

Going from PNG to PDF means wrapping: the image is placed on a page sized to match its pixel dimensions. No new detail is created — the PDF is just a container around the same pixels. This is useful when you need to submit an image as a "document" (upload forms that only accept PDF, for example).

Need to convert right now?

The PDF to PNG converter turns every page into its own PNG at up to 600 DPI, free and entirely in your browser — see the step-by-step guide for tips on picking the right DPI. Going the other way? PNG to PDF wraps your images into a document in seconds.

Bottom line

Use PDF when the content is a document: multi-page, text-heavy, meant for reading or printing or signing. Use PNG when the content is an image: a single visual you want to embed, edit, or share without a viewer. The two formats complement each other, and converting between them is a one-step operation either way.