Compress WebP Images Online for Free
Reduce WebP file sizes with the quality slider and instant preview. Preserve transparency and take advantage of WebP’s superior compression. All processing happens in your browser.
How to Compress a WebP Image
Reducing your WebP file size with ImageSizr.com is quick and straightforward:
- Upload your WebP file — drag and drop, click browse, paste from clipboard (Ctrl/Cmd+V), import from a URL, or connect Google Drive, Dropbox, or OneDrive.
- Adjust the quality slider — the default is 80%, which provides a good balance of quality and file size. Move it lower for smaller files or higher for better visual fidelity.
- Review the preview — use the before/after split-view to compare quality and check the resulting file size.
- Download — click Download to save your compressed WebP image.
Use the Calculate Sizes button to compare file sizes at different quality levels before committing. This helps you find the ideal setting for your specific use case.
Why WebP Is Already Efficient
WebP uses advanced compression algorithms developed by Google that produce smaller files than both JPEG and PNG at equivalent visual quality:
- Lossy WebP is typically 25–34% smaller than JPEG at equivalent quality, making it ideal for photos and complex images on the web.
- Lossless WebP is approximately 26% smaller than PNG, perfect for graphics where every pixel matters.
- Both modes support transparency, combining the best of JPEG’s compression efficiency with PNG’s alpha-channel support.
Even after initial encoding, further compression with a lower quality setting can significantly reduce file size. This is especially useful when optimizing WebP assets for Core Web Vitals and page speed performance. Read more about format advantages in our guide: JPG vs PNG vs WebP — when to use each.
WebP Transparency and Compression
WebP supports alpha-channel transparency similar to PNG, but with much smaller file sizes. When you compress a transparent WebP image on ImageSizr.com, the transparency is fully preserved.
Use the background toggle to switch between light and dark checkerboard previews. This lets you verify which areas of your image are transparent before downloading.
- WebP output — preserves transparency with the best compression ratio.
- PNG output — preserves transparency with broader compatibility but larger file sizes.
- JPEG output — does not support transparency. Transparent areas are filled with a background colour.
WebP combines the transparency of PNG with the compression efficiency of JPEG, making it the optimal choice for modern web projects.
WebP Browser Compatibility
WebP is supported by all major modern browsers, making it a safe choice for web projects:
- Chrome — supported since version 17.
- Firefox — supported since version 65.
- Safari — supported since version 14.1 (macOS Big Sur and iOS 14).
- Edge — supported since version 18.
For legacy browsers that do not support WebP, consider providing JPEG or PNG fallbacks. Most modern CMS platforms, CDNs, and image services also support WebP natively. Learn more about choosing the right quality settings for each format.
Related Tools for WebP Workflow
- Resize WebP images — change pixel dimensions to further reduce file size alongside compression.
- Crop your WebP image — remove unnecessary areas before compressing to reduce pixel count.
- Resize your WebP image — change dimensions to the exact size you need.
- Compress images in any format — use the general compressor for any supported image type.
- Compress PNG images or Compress JPG images for other formats.
- Crop tool — crop any image format with the interactive editor.
Explore our image optimization guides, including how to compress images for faster web pages.
Frequently Asked Questions
How to compress a WebP image?
Upload your WebP file to ImageSizr.com, adjust the quality slider (default 80%), review the before/after preview and resulting file size, and click Download to save the compressed image.
Why is WebP already smaller than JPEG or PNG?
WebP uses advanced lossy and lossless compression algorithms developed by Google. Lossy WebP is typically 25–34% smaller than JPEG at equivalent quality. Lossless WebP is approximately 26% smaller than PNG.
Does compressing WebP remove transparency?
No. WebP output preserves the full alpha channel. Only JPEG export removes transparency by filling transparent areas with a background colour.
Does compression reduce the image dimensions?
No. Compression only changes the file size by adjusting encoding quality. The pixel dimensions stay the same.
How do I choose the right quality level?
Start at 80% for a good balance of quality and size. Use the before/after split-view preview to compare results visually before downloading.
Is WebP compatible with all browsers?
WebP is supported by all major modern browsers including Chrome, Firefox, Safari (14.1+), and Edge. For legacy browsers, consider JPEG or PNG fallbacks.
Is ImageSizr free to use?
Yes. ImageSizr is completely free with no account or sign-up required.
Are my images uploaded to a server?
No. All processing happens directly in your browser. Your images never leave your device, so your data stays private.