About
Why we built it
Search for a way to convert a file and you usually get two options: a web service that wants you to upload the file, or a program you have to install. The first is awkward for anything private — a recorded meeting, a photographed contract — and the second is a lot of ceremony for a one-off job.
SOMKYU Converter exists to be a third option. Modern browsers can already decode audio, draw images and run video codecs compiled to WebAssembly. Used directly, that means a file can be converted without ever leaving the machine it is on.
How it works
Opening a page downloads the code it needs; from then on every calculation happens on your device. Audio goes through WebCodecs and our own Ogg muxer, images through Canvas, video through FFmpeg compiled to WebAssembly. Results are handed straight from browser memory to your downloads folder.
Once the required engine and libraries are ready in an open page, processing may work offline. Reopening the site offline is not supported. Browser memory and codecs limit which files can be processed. Results have no watermark.
Open the Network tab of your browser’s developer tools while converting and you can see for yourself that no file is uploaded.
The articles and figures on this site
Sizes, times, frequencies and other figures in the guides and tool descriptions were measured by converting the same source files with the tools on this site. Each article states the source, the settings, and the browser and operating system used. Where synthetic audio or generated images were used as test material, the article says so.
Results change with the environment, so convert important files yourself to check. If you tell us about a mistake through Contact, we check it, fix it and record it in Updates.
The tools
- Audio Converter — MP3, WAV, FLAC, M4A input → OGG (Opus), MP3, WAV output, with waveform preview
- Audio Cutter — select a range on the waveform and save it as WAV, MP3 or OGG (delete a range, fades; WAV keeps the source samples)
- Image Converter — PNG, JPEG, WEBP, BMP conversion, resizing, plain-background removal
- Video Converter — MP4, WEBM, MOV, MKV, AVI and GIF in any direction
- Video to GIF — pick part of a video and save it as a GIF with your own size, fps, colours and speed (crop, size estimate)
- Image Crop — exact pixel values or drag, with ratio presets
- App Icon Generator — 74 iOS, macOS, watchOS and Android sizes plus an Xcode catalog
- TGA Viewer — open game-texture TGA files and save as PNG, JPG, WEBP or BMP (8–32-bit, RLE, alpha)
Frequently asked questions
Are my files sent to or stored on a server?
No. Selected files are processed inside your browser, and there is no code that sends their contents to a server. Working memory is released when you close the page. The page does make requests to load itself, libraries, ads and fonts; see the Privacy Policy for details.
Is there a price or a file limit?
Every tool is free, needs no sign-up or login and adds no watermark. There is no usage limit, but the largest file you can handle at once depends on your device memory and browser. Long, high-resolution videos are more reliable on a PC.
Can I use it on my phone?
Yes. Open it in your phone’s browser and pick photos and videos from your gallery. OGG output only works in browsers with a WebCodecs audio encoder (recent Chrome or Edge), and long videos may fail on devices with little memory. Some features may behave differently in Safari on iPhone.
Does it work without an internet connection?
Once a page is open and the engine and libraries it needs are ready, conversion may keep working if the connection drops. There is no way to open the site offline, though, so you need a connection to load a page and to download the video engine the first time.
Does converting lower image or sound quality?
It depends on the format. PNG and BMP store pixels as they are, while JPEG, WEBP, MP3, OGG and MP4 discard some information as they compress, so quality and bitrate settings matter. Turning a compressed MP3 into WAV does not bring lost quality back. Measurements by format are in our guides.
Can I use it for work or commercial projects?
Yes. You own what you convert, and you can use the tools for free for personal or business work. Processing files that infringe someone else’s copyright is prohibited by the Terms of Service, and you are responsible for the files you process.
Who runs it
Feature requests and bug reports are welcome by email. Telling us which format you wish we supported is the most useful thing you can send.
The site is free to use, and its running costs are covered by advertising. Ads are placed only where they are clearly separate from the tools’ buttons.