PureTools
Convert Any Video to MP4 or WebM Instantly
Convert any video to MP4 or WebM directly in your browser, choose format, resolution and quality. No upload, no watermark, no signup, works offline.
Drop your video here
or click to browse
Output format
Resolution
Quality
Only applies when re-encoding is required. When source and target formats are compatible, quality is always preserved regardless of this setting.
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How to use the Video Converter
This tool converts video files entirely in your browser. Choose your output format (MP4 or WebM), set an optional resolution and quality level, then click Convert. No file is ever sent to a server, all processing happens locally in your tab.
- Select your video, drag and drop a video file onto the drop zone, or click Browse. MP4, MOV, AVI, WEBM and MKV formats are supported. MP4 output accepts up to 500 MB; WebM output accepts up to 200 MB on desktop and 100 MB on mobile.
- Choose an output format, MP4 for universal device compatibility or WebM for the web and smaller file sizes.
- Set resolution and quality, leave both at Original to keep the source settings, or choose a target resolution (1080p, 720p, 480p, 360p) and a quality level (Original, High, Balanced, Fast).
- Set the output filename, the field is pre-filled with your source filename. Change it as needed; the correct extension is added automatically based on the chosen format.
- Click Convert Video, on the first use, the tool downloads a one-time local converter file (~30 MB). After that, subsequent conversions load instantly from your local cache.
- Download your file, the result shows original and converted sizes. Click Download to save. No watermark is added to any output format.
When to use each output format
MP4 (H.264 + AAC) is the safest choice for compatibility, it plays natively on every phone, tablet, smart TV, social platform and browser without any plugins. If you are unsure which format to use, pick MP4. WebM (VP8 or VP9 + Opus) is recommended for websites and web apps when you want an open web format that loads well in modern browsers. It is not supported by older iOS devices, so avoid it for general sharing.
How quality and resolution affect file size
Resolution and quality both independently affect the output file size. Halving the resolution (e.g., from 1080p to 720p) roughly reduces the file size by 50–60%. Switching from Best quality to Balanced quality typically cuts an additional 30–50% from the remaining size. Combining a resolution reduction with a quality reduction is the most effective way to target a specific file size. For precise file size targets, use the Video Compressor which lets you specify an exact output size in MB.
Frequently asked questions
Is my video uploaded to a server?
No. Your video file never leaves your device. The entire conversion runs inside your browser without any server involvement. PureTools has no infrastructure to receive your files, the conversion work happens entirely in your browser tab. You can disconnect from the internet after the page has loaded and conversion will continue without interruption. Your file is held only in your browser's memory and cleared automatically when you close the tab. Your data is never used to train AI models or improve machine learning systems.
What output formats does the converter support?
The converter outputs two formats. MP4 (H.264 video + AAC audio) is the most universally compatible format, it plays on every device, browser, phone and social platform without issues. WebM (VP8 or VP9 video + Opus audio) is optimized for web playback and often creates compact files for websites and HTML video elements. No watermark is added to any output format.
What is the difference between the quality levels?
Quality levels control how much compression is applied when re-encoding is required. When source and target formats are compatible (for example MOV to MP4), the video stream is copied directly without re-encoding, this setting has no effect and quality is always preserved. Original quality is the default and re-encodes at near-lossless settings, preserving the source as closely as possible when a codec change is unavoidable. High produces excellent quality with a noticeably smaller file, a good option when you also want to reduce size. Balanced applies stronger compression with a minor quality reduction, suitable for sharing online. Fast uses the most aggressive compression for the smallest file, at the cost of visible quality loss on complex scenes.
How does the resolution setting work?
Choosing a resolution scales the video to fit within the selected dimensions while preserving the original aspect ratio. For example, selecting 720p on a landscape video scales the height to 720 pixels and adjusts the width proportionally, the video is never stretched or cropped. Landscape, portrait and square videos are all handled correctly. If your source video is already smaller than the selected resolution, it is not scaled up, only downscaling is applied. Selecting Original keeps the source resolution unchanged.
What video formats can I use as input?
The converter accepts five widely used formats: MP4 (the most common container), MOV (Apple QuickTime, used by iPhones and macOS), AVI (Audio Video Interleave, a classic Windows format), WEBM (Google's open web format), and MKV (Matroska, a flexible open-source container). These formats cover the vast majority of everyday video files. MP4 output accepts source files up to 500 MB. WebM output uses stricter limits because it is more demanding in the browser: 200 MB on desktop and 100 MB on mobile.
Is there a file size limit for the input?
Yes. MP4 conversion accepts source files up to 500 MB. WebM conversion is limited to 200 MB on desktop browsers and 100 MB on mobile browsers to protect device RAM. This difference exists because browser-side WebM encoding is heavier than MP4 remuxing or H.264 output. If your source is larger, choose MP4, reduce the resolution, trim the clip, or compress it first before converting to WebM.
Does the tool work offline?
Yes, after your first visit. The tool saves the files it needs locally on your device on the first load, including a one-time converter file (~30 MB). On all subsequent visits, including offline, the page loads from your local cache. Conversion runs entirely without an internet connection once the tool has been visited once. These cached tool files are not deleted between sessions unless you manually clear browser data. For the most reliable offline use, open the merger once while online, then keep the browser cache intact before using it without a connection.
Is my data erased when I close the tab?
Yes, completely. Your video file exists only in your browser's memory while the tab is open. Your format, resolution and quality preferences are saved for the current session only and erased automatically when you close the tab. No file content, video data or personal information is ever written to permanent storage by this tool or transmitted to any server. Closing the tab clears everything instantly and permanently.