How to Convert PNG to WebP and Compress It Online

WebP is an image file format that supports both lossy and lossless compression, along with transparency. Converting a PNG to WebP can make screenshots, webcam captures, thumbnails and graphics smaller for web pages and messaging. This guide walks through doing the conversion with an online compressor and checking that the result is usable.

Before you start

Find out where the conversion happens. Some online converters process images inside your browser, while others upload files to a remote server. The tool's own description or privacy information should say which applies. If it does not, assume the image leaves your device, and avoid using it for screenshots that show personal data, documents, faces or account details.

• Keep a copy of the original PNG. Conversion creates a new file, and lossy compression cannot be undone.
• Note the image's pixel dimensions and whether it has a transparent background, so you can compare them after conversion.
• Check that the place where you will use the image accepts WebP. Most current browsers display it, but some upload forms, older apps and editing programs only accept PNG or JPEG.
• If the tool has file size or count limits, check them before uploading a large batch.

Step-by-step instructions

• 1. Open the online PNG to WebP converter and add your file, usually by dragging it onto the page or using the file picker.
• 2. Choose the compression mode if the tool offers one. Lossless keeps every pixel identical to the PNG; lossy discards some detail to reach a smaller file.
• 3. If you choose lossy, set the quality level. Lower values give smaller files but more visible artifacts. Start near the tool's default and adjust after checking the result.
• 4. If the image has transparency, make sure any option for alpha or transparency is enabled and that no background color fill is selected.
• 5. Resize only if needed. If the image is larger than it will ever be displayed, reducing its pixel dimensions often saves more space than lowering quality. Keep the aspect ratio locked so the picture is not stretched.
• 6. Start the conversion and download the WebP file. Save it under a new name so the original PNG stays untouched.

Lossless mode suits screenshots with small text, interface elements, logos and line art, where lossy artifacts are easy to notice. Lossy mode usually works better for photos and camera frames, where minor detail loss is hard to see.

If you prefer to work offline, the cwebp command-line encoder from Google's libwebp package performs the same conversion locally. For example, cwebp -q 80 input.png -o output.webp produces a lossy file, and adding -lossless produces a lossless one. Check the documentation for your installed version before relying on other options.

Check the output

• Compare file sizes in your file manager. The WebP file should be smaller than the PNG; if not, see the problems section below.
• Open the WebP in a browser or image viewer and confirm the pixel dimensions match what you expect.
• View it at 100% zoom and look for blur on text, color banding in gradients and blocky noise around sharp edges.
• Place a transparent image over a colored background to confirm the transparent areas did not turn white or black.
• Test the file where you actually plan to use it, such as a website, chat app or document, since support varies between programs.

Metadata such as camera details, creation dates or embedded color profiles may be removed during conversion, depending on the tool. If you need this information, check whether it survived; if privacy is your concern, do not assume it was stripped without checking.

Common problems and next steps

The WebP file is bigger than the PNG. This can happen with lossless mode, especially for small graphics or PNGs that were already heavily optimized. Try lossy mode at a moderate quality, reduce the pixel dimensions, or keep the original PNG if it is already the smaller file.

Transparency disappeared. The tool may have flattened the image onto a solid background. Re-convert with the transparency option enabled, or use a different converter that states it preserves the alpha channel.

Text or edges look fuzzy. Raise the quality setting or switch to lossless. Lossy compression handles sharp, high-contrast detail less well than smooth photographic content.

Colors look slightly different. The original PNG may contain a color profile that was dropped or handled differently. Compare both files in the same viewer; if the difference matters, try a tool that keeps embedded color profiles.

A website or app rejects the file. The destination may not support WebP. Upload the original PNG instead, or convert to JPEG if transparency is not needed and the destination requires a smaller file.

You need to convert many images. Choose a converter that supports batch processing, or use a local command-line tool so files are not uploaded one by one. Use the same settings for every image and spot-check a few results before replacing originals.