File formats explained

What is a HEIC file? PDF vs Word? PNG or JPG? Clear, jargon-free answers to the format questions that come up most — what each one is, when to use it, and how to open or convert it.

PDF

What Is a PDF File? Uses, Pros and Cons Explained

PDF is the format for documents that need to look the same everywhere. Here is what a PDF actually is, when to use one, its trade-offs, and how to open, edit and convert it.

HEIC

What Is a HEIC File? Why iPhone Photos Use It and How to Convert

HEIC is the high-efficiency photo format iPhones save by default. Here is what it is, why photos in it will not open everywhere, and how to convert HEIC to JPG or PNG.

WebP

What Is a WebP File? The Web Image Format Explained

WebP is a modern image format that makes web pages faster by producing smaller files than JPG or PNG. Here is how it works, its trade-offs, and when to use or convert it.

DOCX

What Is a DOCX File? The Word Document Format Explained

DOCX is the modern Microsoft Word document format. Here is what it is, how it differs from the old DOC, when to use it, and how to open, edit and convert it to PDF.

PNG vs JPG

PNG vs JPG: Which Image Format Should You Use?

PNG and JPG are the two most common image formats, and they are good at opposite things. Here is the difference, when to use each, and how to convert between them.

SVG

What Is an SVG File? Vector Graphics Explained

SVG is a vector image format that stays razor-sharp at any size. Here is how vector differs from raster, what SVG is best for, its limits, and how to work with it.

CSV

What Is a CSV File? The Simple Data Format Explained

CSV is the plain-text format for tabular data that almost every program can read. Here is what it is, why it is so widely used, its quirks, and how to open one.

Markdown

What Is Markdown? The Plain-Text Formatting Language Explained

Markdown is a lightweight way to write formatted text using plain symbols. Here is what it is, why it caught on, the basic syntax, and how to preview and export it.

JPG

What Is a JPG (JPEG) File? The Photo Format Explained

JPG is the format almost every digital photograph is stored in. Here is what it is, how its compression works, its trade-offs, and how to open, convert and shrink one.

PNG

What Is a PNG File? The Format for Sharp Graphics and Transparency

PNG is the go-to format for screenshots, logos and anything needing a transparent background. Here is how it works, when to use it over JPG, and how to convert it.

GIF

What Is a GIF File? Animation, Limits and Better Alternatives

GIF is the old format behind looping animations and reaction clips. Here is how it works, why it is limited to 256 colours, and when a video or WebP is the smarter choice.

TIFF

What Is a TIFF File? The Format for Print, Scanning and Archives

TIFF is the high-quality image format used in professional print, scanning and archiving. Here is what it is, why the files are so large, and how to convert one for everyday use.

AVIF

What Is an AVIF File? The Next-Generation Image Format

AVIF is a modern image format that squeezes photos smaller than JPG or WebP. Here is how it works, where it is supported, and how it compares to WebP and JPG.

BMP

What Is a BMP File? The Uncompressed Bitmap Format Explained

BMP is an old, uncompressed Windows image format that stores every pixel raw. Here is what it is, why the files are huge, and why you should almost always convert it.

ICO

What Is an ICO File? The Icon and Favicon Format Explained

ICO is the Windows format behind app icons and website favicons. Here is what it is, why it holds several sizes at once, and how to create one from a PNG.

XLSX

What Is an XLSX File? The Excel Spreadsheet Format Explained

XLSX is the modern Excel spreadsheet format. Here is what it is, how it differs from the old XLS and from CSV, and how to open and edit one without Excel.

PPTX

What Is a PPTX File? The PowerPoint Presentation Format Explained

PPTX is the modern PowerPoint presentation format. Here is what it is, why the files get so large, and how to open, edit and shrink one without PowerPoint.

TXT

What Is a TXT File? Plain Text Explained

TXT is the simplest document format there is — pure text with no formatting. Here is what that means, why it is so durable, and the encoding quirks worth knowing.

JSON

What Is a JSON File? The Data Format Behind Apps and APIs

JSON is the plain-text format apps and websites use to exchange structured data. Here is what it is, what its structure looks like, and how to read, format and validate it.

RTF

What Is an RTF File? Rich Text Format Explained

RTF is a document format that keeps basic formatting while opening in almost any word processor. Here is what it is, when it beats DOCX or plain text, and how to convert it.

EPUB

What Is an EPUB File? The Ebook Format Explained

EPUB is the open standard for ebooks, with text that reflows to fit any screen. Here is how it works, how it differs from a PDF ebook, and how to open one.

ZIP

What Is a ZIP File? Compressed Archives Explained

A ZIP file bundles many files into one compressed archive. Here is what it is, how the compression works, why it is everywhere, and how to open or create one.

WebP vs AVIF

WebP vs AVIF: Which Modern Image Format Should You Use?

WebP and AVIF are the two modern formats that beat JPG for web images. Here is how they differ in size, quality and support, and which one to reach for.

XLSX vs CSV

XLSX vs CSV: Which Spreadsheet Format Should You Use?

XLSX and CSV both hold tabular data, but they solve different problems. Here is the difference, when to use each, and the pitfalls of moving data between them.