What Is My User Agent — Device & Browser Information

What Is My User Agent — Device & Browser Information. Instantly check your user agent string, screen resolution, browser details, CPU cores, memory, and device capabilities — all running in your browser, nothing uploaded.

Instantly check your user agent string and screen resolution with our free online device information tool.

This essential web-development utility reads your browser's internal APIs to surface exact screen dimensions, device pixel ratio, viewport size, browser vendor, platform, and the complete user agent — everything you need for responsive-design debugging, browser-compatibility checks, and writing accurate bug reports.

Developers, QA testers, and support engineers all rely on a fast, reliable user agent checker to verify client environments without installing extensions or running scripts.

Beyond the basics, our device information tool also exposes browser capabilities that most checkers miss: logical CPU core count, available device memory, maximum touch points, cookie status, and online/offline state.

Competitor tools like WhatIsMyBrowser.com and DeviceInfo.me surface these fields — ours does the same, 100 % client-side, so none of your hardware metrics are sent to an external server.

Whether you need a quick screen resolution checker or a full hardware profile, open this page and your results appear instantly.

Instantly check your user agent string , screen resolution , browser details, CPU cores, device memory, and more with our free device information tool. What Information Is Shown? Screen size, window size, color depth, and pixel ratio.

Browser vendor, platform, languages, and full user agent string. CPU cores, device memory, touch points, cookie status, and online status. Why Check Your Device Info?

Use this tool for debugging responsive layouts, verifying media query breakpoints, checking browser compatibility, or copying your user agent for support tickets. All data is read locally — nothing is sent to a server.

Related tools: User-Agent Parser , HTTP Headers Parser , Keycode Info .

Frequently asked questions

What is my user agent?

Your user agent string is shown in the Device section under User agent. It is the text your browser sends to websites to identify its name, version and operating system, read here from navigator.userAgent.

Why is the screen size different from my monitor's resolution?

Screen size shows the space available to windows in CSS pixels, which excludes the taskbar or dock and is scaled by the operating system. Multiply it by the Pixel ratio to estimate physical pixels: for example 1440 x 900 at 2 dppx is about 2880 x 1800.

What is the difference between screen size and window size?

Screen size is the area available on your display, while Window size is the current inner size of the browser viewport. Window size updates live as you resize the browser, which is handy when testing responsive layouts.

Why do some fields show unknown?

Some values come from browser APIs that are not available everywhere. Device memory uses navigator.deviceMemory, which only Chromium-based browsers provide and which is rounded for privacy, and Browser vendor is empty in Firefox. Missing values are shown as unknown.

Is my device information sent anywhere?

No. Everything is read from your browser's own JavaScript APIs and displayed on the page; the tool does not upload or store it.

How to use this online tool

What Is My User Agent — Device & Browser Information is designed for fast browser workflows when you need to format, validate, convert, decode, encode, generate, or inspect data without opening a heavy desktop app. Start with the input field or visible options, review the result, then copy or download the output for the next step.

Private processing in your browser

What Is My User Agent — Device & Browser Information keeps the normal processing step local in your browser. That is useful for code snippets, tokens, documents, configuration values, text samples, and other material that should not be sent to a remote service unless you explicitly choose to share it.

When this tool is useful

Use What Is My User Agent — Device & Browser Information for repeatable developer tasks, technical documentation, QA checks, quick conversions, debugging, content cleanup, and internal team workflows. The page focuses on clear inputs, immediate feedback, and output that is easy to reuse in code, reports, tickets, emails, or notes.

Practical tips

Before copying the final result, check important details such as spacing, casing, filenames, encoding, token structure, line breaks, or output format. Small checks prevent mistakes when the result is reused in source code, API requests, documentation, spreadsheets, or shared files.