Learn and calculate

Tools

25 guides · 3 calculators

Use a browser calculator or open one of 25 clear “What is…?” guides. No account, upload, analytics, or advertising required.

Interactive

Browser tools

3 tools

Aspect ratio calculator

Find a missing dimension or reduce a width and height to a ratio.

Image print size calculator

Convert pixel dimensions and PPI into a physical print size.

URL explorer

Break a web address into browser-normalized components without fetching it.

Reference library

What is…?

25 guides

01Images and videoWhat is aspect ratio?Aspect ratio describes the proportional relationship between an image's width and height.02Images and videoWhat is image resolution?Image resolution usually describes an image's pixel dimensions and, for print, how pixels map to physical size.03Web basicsWhat is a URL?A URL is an address that identifies a resource and describes how to access it.04Images and videoWhat is a pixel?A pixel is one sample in the grid used to store and display a digital image.05Images and videoWhat is PPI?PPI means pixels per inch and relates an image's pixel grid to a physical size.06Web basicsWhat is a domain name?A domain name is a human-readable name used to reach an internet resource.07Web basicsWhat is a query parameter?A query parameter is a name-and-value entry carried in the query portion of a URL.08Web basicsWhat is a URL fragment?A URL fragment identifies a part of a resource and begins with a hash sign.09Images and videoWhat is image resizing?Image resizing changes an image's pixel dimensions or displayed dimensions.10Images and videoWhat is image cropping?Image cropping removes pixels from the outer parts of an image to change framing or shape.11Images and videoWhat is image compression?Image compression represents image data using fewer bytes, either losslessly or with some discarded information.12Images and videoWhat is a JPEG?JPEG is a widely supported lossy image format commonly used for photographs.13Images and videoWhat is a PNG?PNG is a lossless raster image format with support for alpha transparency.14Images and videoWhat is an SVG?SVG is a text-based open format for describing two-dimensional vector graphics.15Images and videoWhat is DPI?DPI means dots per inch and commonly describes the placement of physical printer dots.16Images and videoWhat is image transparency?Image transparency allows pixels to reveal some or all of the content behind an image.17Web basicsWhat is a hostname?A hostname identifies the host portion of a network address such as a URL.18Web basicsWhat is a URL path?A URL path identifies a location within the scope of a scheme and host.19Web basicsWhat is a web protocol?A web protocol is a shared set of rules used by software to communicate.20Web basicsWhat is HTTPS?HTTPS is HTTP carried over an encrypted, authenticated transport connection.21Web basicsWhat is an IP address?An IP address identifies a network interface so internet data can be routed to and from it.22Web basicsWhat is AI?Artificial intelligence is a broad term for machine-based systems that produce outputs such as predictions, recommendations, or content.23Web basicsWhat is a VPN?A VPN creates an encrypted connection between a device and a VPN endpoint across another network.24Web basicsWhat is an API?An API is a defined interface through which software components request data or behavior from one another.25Web basicsWhat is cloud computing?Cloud computing provides configurable computing resources over a network on demand.