Video Resolution Checker
Drop in any video to see its width, height, total pixels, megapixels, aspect ratio, orientation, and standard resolution name (4K, 1080p, etc). Files are read entirely in your browser — no FFmpeg required for this one.
About Video Resolution Checker
Video Resolution Checker runs the video editing and conversion job locally inside your browser. Drop in any video to see its width, height, total pixels, megapixels, aspect ratio, orientation, and standard resolution name (4K, 1080p, etc). Files are read entirely in your browser — no FFmpeg required for this one. The work happens on your machine, the result is generated on your machine, and the page exposes the controls you need to drive it without burying them in menus.
Internally the tool runs on FFmpeg compiled to WebAssembly — the same processing stack used by professional desktop pipelines, just compiled for the browser. MP4, WebM, MOV, MKV, AVI, FLV, and OGV files are accepted natively. 500 MB is the practical ceiling, set so the tool stays responsive on phones and older laptops.
Video Resolution Checker works well as a bookmarked utility you reach for when you need it. The first visit shows you what the tool does; the second is when you realise it is a low-friction option for the task and worth keeping in your tab list.
The browser sandbox isolates the page's JavaScript from the rest of the system, the same way it isolates every other tab you have open. Video Resolution Checker works inside that sandbox: it reads the file you give it, processes it with FFmpeg compiled to WebAssembly, and writes the result back. Nothing leaves the page's memory unless you choose to download or copy it.
The hard constraints are easy to remember. Maximum input: 500 MB. Multiple files per run: no — one input at a time, by design, to keep results predictable. The same controls apply on every run.
Video Resolution Checker is intentionally narrow in what it does, which makes it easy to slot into a longer workflow. Take its output, hand it to whichever next tool fits the job, and Video Resolution Checker stays out of your way until the next time you need it.
Video Resolution Checker sees the most use from students submitting video assignments and product teams shipping release demos, but the design is intentionally generic enough that you do not need a specialist background to get a good result. The defaults aim at the most common case so a first-time user can get the right output without changing any settings.
When the job finishes, Video Resolution Checker hands you the result as `{name}-edited.{ext}`. Filenames are derived from your input where possible, so a quick batch of jobs leaves you with a tidy folder rather than a pile of generic "output (3)" files. Nothing is auto-saved on Favtoo's side because nothing was ever sent there.
Some notes on the design of Video Resolution Checker. The page is intentionally narrow: one input, the controls relevant to the task, and one output. Adding unrelated features would make the common case slower for the majority of users, so the surface is held to what people actually use.
From a product perspective, Video Resolution Checker is one of the simplest possible expressions of "do one thing well." The catalog contains dozens of related tools that each handle a slightly different video editing and conversion task, and every one is a separate page rather than a tab inside a larger app. That separation keeps each tool fast to load and easy to bookmark.
A few practical tips that experienced users of Video Resolution Checker pick up over time. First, keep your default browser updated — the engine relies on standard web APIs and newer browser versions are noticeably faster than ones from a few years ago. Second, close other heavy tabs before processing a large input; the engine shares CPU and memory with whatever else is open. Third, if you re-run the same kind of job often, your last-used settings are remembered for the rest of the tab session, so subsequent runs are essentially one click.
Video Resolution Checker runs as a regular web page, so there is no install step or permission grant before the first run. The page can be audited by viewing the source or by watching the developer-tools Network tab while a job runs.
Common gotchas worth flagging: Video Resolution Checker only accepts MP4, WebM, MOV, MKV, AVI, FLV, and OGV, so if your file is in another format you will need to convert it first. The 500 MB ceiling is per-file, not per-session; you can run as many separate jobs as you like, but a single oversized input will be rejected on load.
That is essentially everything Video Resolution Checker does and how it does it. Open the tool above, drop in your input, and the work happens in the page. If you find yourself reaching for it often, bookmark the page — it loads quickly on subsequent visits, and your most-recent settings are remembered for the rest of the session.
How it works
- 1Open Video Resolution Checker in your browser. The page loads quickly and the tool is ready to use the moment it becomes interactive.
- 2Drop a MP4, WebM, MOV, MKV, AVI, FLV, and OGV file onto the upload area, or click to pick one from your device.
- 3Adjust the options to match what you need. Sensible defaults cover the most common case, so you can usually skip this step.
- 4Click to start the job. The engine (FFmpeg compiled to WebAssembly) processes the input in the page; you can watch the progress indicator until it completes.
- 5Grab the output named `{name}-edited.{ext}` as soon as the run completes. You can also copy the result instead of downloading if the next tool in your workflow accepts pasted input.
- 6Run additional jobs as needed. The same controls and defaults apply on every run.
Common use cases
- Compress a demo video small enough to attach to an email using Video Resolution Checker.
- Re-encode a clip so it plays on an older device without stuttering.
- Strip the audio track from a screencast for a silent loop.
- Convert a phone-recorded clip into a web-friendly MP4.
- Trim the silent intro from a screen recording before sharing it.
- Cut a long meeting recording down to the relevant five minutes.
- Add a quick caption overlay before posting to social.
- Extract a still frame from a video for use as a thumbnail.
Frequently asked questions
How does it work without uploading?
The browser's native HTML5 video element loads your file as a Blob and exposes its videoWidth and videoHeight properties. We then compute the aspect ratio, total pixels, megapixels, and the standard resolution name — entirely on your device.
Why is this tool faster than the others?
It does not need to load FFmpeg WebAssembly. The browser already has a video decoder built in, so we simply read the dimensions from the file header. Results appear in well under a second.
Why is in-browser still slower than online tools for huge files?
Even reading the header requires loading the file into a Blob, which takes time on large files. The trade-off is total privacy: your video never leaves your device.
What does each result mean?
Width and height are in pixels. Total pixels = width × height. Megapixels is that divided by a million. Aspect ratio is the simplified width:height fraction (e.g. 16:9). Orientation classifies whether the video is landscape, portrait, or square.
Why is my 3840×1600 not labeled "4K"?
The standard 4K UHD label means 3840×2160. Cinema 4K is 4096×2160. Ultra-wide formats like 3840×1600 are non-standard, so we just call them by their resolution.
What about Pixel Aspect Ratio (PAR)?
This tool reports stored pixel dimensions. If your file uses non-square pixels (rare in modern files), the displayed aspect ratio may differ from the encoded DAR. Use the Video Metadata Viewer for full PAR/DAR info.
How big a file can I check?
Up to 500MB. Reading the header is fast even on huge files because we don't decode any frames.
Is my video uploaded?
No. The check runs entirely in your browser tab. Nothing is transmitted, stored, or logged. Closing the tab erases the file from memory immediately.
Does Video Resolution Checker require a browser extension or plug-in?
No installation is needed. Video Resolution Checker runs as a normal web page, with no browser extension, no native helper, and no separate desktop client to download. That is partly a privacy choice — extensions can request broad permissions, while a regular page is sandboxed by default — and partly a convenience one: you can use Video Resolution Checker on any computer you have temporary access to without leaving anything installed on it.
Can I call Video Resolution Checker from a script?
Video Resolution Checker is a browser-only tool by design and does not expose a hosted API. The reason is the same as the privacy story: there is no Favtoo backend doing the work, so there is no service to call. If you need to script the same transformation, the underlying engine (FFmpeg compiled to WebAssembly) is open-source and can be used directly from your own code.
Are there any usage limits on Video Resolution Checker?
Inputs are capped at 500 MB per file, which keeps memory usage stable across phones, tablets and older laptops. You can run Video Resolution Checker as often as you need; every run produces a full-quality result.
How accurate is Video Resolution Checker?
Video Resolution Checker is built on FFmpeg compiled to WebAssembly, which is the same class of engine used by professional video editing and conversion pipelines. For deterministic operations, the output is byte-identical to what an equivalent CLI run would produce; for operations involving a codec or a model, the result is well within the range of what comparable tools generate. If you have a specific reference output you need to match, run a small test job first to confirm the configuration produces what you expect.
Why does Video Resolution Checker feel slow on large inputs?
Most jobs finish in seconds. Speed scales with input size and with how many CPU cycles your browser tab has available — the engine runs in your browser, so it shares resources with whatever else you have open. For inputs near the 500 MB ceiling, expect anywhere from a few seconds to roughly a minute on a typical laptop. Closing other heavy tabs noticeably speeds things up.
Is Video Resolution Checker really free?
Video Resolution Checker is free to use. The processing runs in your browser, which keeps the per-user cost low enough that the tool can be offered openly. The download is the same file the engine produced — you can use it for as many runs as you need.
Can Video Resolution Checker run inside a corporate firewall?
Video Resolution Checker is a static page running an open-source engine in your browser, so a typical corporate firewall does not get in the way as long as it allows JavaScript and WebAssembly to load from Favtoo. For teams that need to host it themselves on an internal network, the underlying engine (FFmpeg compiled to WebAssembly) is open-source and can be packaged into a private build with the same behaviour. Reach out via the Contact page if that is something you are exploring.
Does Video Resolution Checker work with screen readers?
Video Resolution Checker uses native HTML controls wherever possible, which means keyboard navigation, focus rings, and screen-reader labels work the way the platform expects. The drop zone accepts files via the keyboard-accessible file picker as well as drag-and-drop, and result downloads use standard browser download flows. If you spot an accessibility gap, Favtoo treats it as a bug worth fixing.
What input formats are supported by Video Resolution Checker?
Video Resolution Checker accepts MP4, WebM, MOV, MKV, AVI, FLV, and OGV. If your input is in a format that is not directly supported, convert it first using one of Favtoo's converter tools — every Favtoo converter outputs a file that is a clean input to the next tool in the chain.