What Is My User Agent?
See your browser's user agent string and exactly what it reveals about you.
This user agent checker shows the user agent string your browser sends with every request, then breaks it down into plain language: which browser and version you are running, your operating system, whether you are on desktop or mobile, your language, whether cookies are enabled and how many CPU cores your device reports. It is handy for filing a bug report, testing responsive behaviour, or just seeing what a website learns about your setup.
Everything here runs entirely in your browser. The user agent string and the related details are read directly from your browser's own properties, with nothing sent to a server and nothing stored. What you see is exactly what any site you visit could read from the same properties.
A user agent is a short line of text a browser includes with each request to identify itself, for example listing 'Chrome', a version and the OS. Sites use it to serve the right layout, offer the correct download, or work around known browser quirks. It is a rough identity card, not a precise fingerprint, and it can be changed or spoofed.
How to check your user agent
- Open the page. Your user agent string appears at the top automatically.
- Read the breakdown below: browser, version, operating system and device type.
- Check the extra signals: language, cookies enabled and reported CPU cores.
- Click Copy to grab the full user agent string for a bug report or test.
- Open the page in another browser or device to compare their strings.
Why sites read your user agent, and its limits
Websites use the user agent to make quick decisions: send the mobile layout to a phone, offer the Windows installer rather than the Mac one, or apply a fix for a specific browser version. Analytics tools use it to report the browser and OS mix of their visitors.
It is not reliable as proof of identity. The string can be edited, and browsers increasingly reduce the detail they include to limit tracking, so two very different setups can report nearly the same thing. Read it as a helpful hint about a visitor, never as a guarantee. The details here are what your browser exposes today, and they may look less specific than older strings by design.
How to read the parts of the string
A typical user agent looks intimidating but follows a loose pattern. It usually opens with 'Mozilla/5.0' for historical reasons that no longer mean anything, then lists a platform token in brackets (such as 'Windows NT 10.0' or 'iPhone'), followed by a rendering-engine hint like 'AppleWebKit', and finally the browser and version, for example 'Chrome/120.0' or 'Safari/17'. The breakdown on this page pulls those pieces out so you do not have to parse them by eye.
The quirks are worth knowing. Most browsers still include 'Mozilla' and 'like Gecko' as legacy compatibility tokens, Chrome-based browsers list both 'Chrome' and 'Safari', and Edge adds 'Edg'. Because so many browsers imitate each other's tokens for compatibility, the safest way to read a string is to look at the whole pattern rather than trusting any single word in it.
How these values are read
Every value on this page comes from properties your browser exposes to JavaScript: navigator.userAgent for the string itself, plus related properties for language, cookie status and the reported logical CPU count. No request is made to any server to obtain them, which is why the tool works offline and stores nothing. It is simply reading what the browser already holds in memory and presenting it clearly.
That makes this one of the pure client-side tools on the site, in contrast to an IP or DNS lookup, which must contact an external service to get their answer. Here the data never leaves your device. The practical upshot is that what you see is precisely what a website reads from the same properties the moment you visit it, with no extra exposure created by checking.
When checking your user agent is useful
The most frequent case is bug reporting. When you tell a developer 'the page breaks for me', the single most useful thing you can attach is your exact user agent string, because it pins down the browser, version and OS where the problem appears. Copying it from here is faster and more accurate than describing your setup in words, and it removes the guesswork from reproducing the issue.
It also helps web developers and testers confirm what their site actually receives across devices, check that a responsive layout is being triggered by the right conditions, and verify that a spoofed or emulated user agent in dev tools is taking effect. For everyday users, it is simply a clear window into one of the main things a website learns about you the instant you connect.
Privacy, fingerprinting and the reduced user agent
On its own, a user agent is a coarse signal, but combined with other browser details it contributes to a fingerprint that can help track you across sites without cookies. Browser makers know this, which is why the trend is towards 'reduced' user agents that freeze or drop fine-grained version and platform detail, and towards Client Hints, a system where a site must actively request extra detail rather than receiving it in every request by default.
That is why your string may look shorter, rounder or vaguer than one you remember from a few years ago. It is a deliberate privacy improvement, not a fault, and it means you should expect the level of detail here to keep shrinking over time. The values shown are whatever your current browser chooses to expose today, which is exactly the point of the tool: to reflect reality rather than an idealised full string.
Limits, spoofing and accuracy
A user agent is self-reported and trivially changeable. Browser dev tools, extensions and command-line flags can set it to anything, so bots routinely masquerade as ordinary browsers and privacy tools deliberately blend in. For that reason no serious system should treat the user agent as proof of who or what a visitor is; it is a hint to be corroborated, never an authentication.
Even honest strings have accuracy limits. Reduced user agents mean the version or exact OS build may be rounded or generic, and derived facts like device type are inferred from tokens rather than measured, so an unusual device can be classified loosely. The reported CPU core count is likewise an approximate, sometimes privacy-capped figure meant to help pages size their work, not a precise hardware readout.
Related browser and network tools
The Screen Resolution checker is the natural companion here: together, your user agent and your screen and viewport dimensions describe the environment a site adapts its layout to, which is exactly the pair a developer wants when reproducing a display bug. Both read purely from the browser and send nothing anywhere.
When a problem turns out to be connectivity rather than the browser, the What Is My IP and IP Address Lookup tools help you check your address and where it appears to originate, and the DNS Lookup tool confirms a domain is resolving correctly. Keeping these on hand covers most of the 'is it my browser or my network' questions that come up day to day.
Frequently asked questions
Is this user agent tool free?
Yes, free with no account and no limits. Check your user agent as often as you like.
Is any of this sent to a server?
No. Every value is read from your own browser with JavaScript and shown locally. Nothing is uploaded, logged or stored, so it is safe to use anywhere.
What is a user agent string?
It is a line of text your browser sends with each request to identify the browser, its version and your operating system. Sites use it to serve the right layout and downloads.
Can I change or fake my user agent?
Yes. Browsers and dev tools let you override it, which is common for testing. Because it can be spoofed, sites should never treat the user agent as proof of who you are.
Why does my user agent look shorter or vaguer than expected?
Modern browsers deliberately trim the string and freeze some values to reduce fingerprinting and tracking. Less detail is normal and intended, not a fault with this tool.
Why does it show a certain number of CPU cores?
Browsers expose an approximate logical core count so pages can size their workload. It is a hint from your device, may be capped for privacy, and is not a precise hardware readout.