Stayput

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Convert PNG to WebP

Smaller images for your website, transparency included.

Convert PNG images to WebP in your browser to shrink them for the web. It is free, needs no account and adds no watermark, and your files are not uploaded: everything runs in your browser on your device. The size limit is your device’s memory, and phones hold less; give the page a short while after one visit to save itself for offline use, and then it works offline.

Drop PNG files hereor click to choose files. Batches welcome.

    Working…

    Done

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    Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.

    WebP is what you serve on a website when you want a PNG’s transparency at a fraction of its size. A 400 KB PNG logo or illustration often becomes a 40 KB WebP with no visible difference, which is a real page-speed win. All current browsers display WebP.

    The converter uses your browser’s own WebP encoder where it has one; Safari gets a small built-in WebP encoder that is fetched from this site the first time you save WebP. Quality 80 to 90 is the sweet spot for graphics; for images with fine text, push it to 95. Transparency is preserved.

    How it works

    1. Drop your PNG files onto the page, or tap to pick them. Batches are fine.
    2. Pick a quality. 80 to 90 is a good range for photos; go higher for screenshots with text.
    3. Download each WebP, or all of them as one zip.

    In your browser, not on a server

    Stayput first reads the opening bytes of each file, where every image format writes its signature, so it knows what the file really is whatever it is called. Your browser decodes JPG, PNG, WebP, GIF, BMP, AVIF and SVG itself; TIFF goes through UTIF.js, HEIC through the libheif WebAssembly decoder, and JPEG XL (or AVIF, in a browser without native support) through the Squoosh decoders, all served from this site and cached. The browser re-encodes JPG, PNG and WebP; PDF, ICO, GIF, BMP and TIFF files are written by small encoders in the page. Nothing here needs a server.

    Compared with upload-based tools: Online converters upload your image, convert it on their machine, keep it for hours and cap you at a few files a day. This does the same conversion on your device, for as many files as your device’s memory can hold, with no upload to wait for.

    Verify it yourself. Give the page a short while after one visit to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.

    Questions

    Is WebP transparency preserved?

    Yes. WebP supports an alpha channel, and transparent PNG areas stay transparent.

    Is WebP lossy or lossless?

    It can be either. Browsers encode lossy WebP through this tool, controlled by the quality slider. At quality 100 the result is very close to lossless but still slightly compressed.

    Does it work in Safari?

    Yes. Safari can display WebP but cannot create it itself, so the page loads a small WebP encoder from this site the first time you save one. The picture is still encoded on your device and is not uploaded.

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