PNG to WebP
Convert a PNG to WebP and compare the resulting file. Size changes depend on the image and encoding; inspect transparent edges, fine detail, and the target platform before switching formats.
Convert PNG to WebPNo signup · No uploads · Runs in your browser
What Is WebP?
WebP is an image format that supports lossy and lossless compression, transparency, and animation. It can be useful for web delivery, but conversion does not automatically improve every image: size and appearance depend on the source and encoder settings. Treat the output as a candidate to compare, not an assumed optimization.
There is no dependable percentage saving across all images. A flat illustration, screenshot, photograph, or image with transparency can each behave differently. Compare both file size and appearance, especially around fine lines and transparent edges.
WebP supports transparency (alpha channel) just like PNG, making it a true drop-in replacement for PNG in contexts where the alpha channel is required — logos on transparent backgrounds, UI elements with soft shadows, product photos with clipped backgrounds.
Why Convert PNG to WebP?
For a website, compare the exact asset and delivery path: measure both encoded files, check the server's MIME type, and confirm the intended browsers can display WebP. Keep a PNG fallback for destinations with uncertain support. A smaller image only improves transfer size if the page actually serves that file.
Beyond page speed, CDN bandwidth costs scale directly with image file sizes. A high-traffic website serving millions of image requests per month can see meaningful cost reductions by switching asset delivery from PNG to WebP, often without any change to the serving infrastructure beyond configuring Content-Type headers.
How WebP Compression Works
When converting a PNG to WebP in lossless mode, WebP applies several compression techniques that PNG's DEFLATE algorithm does not use:
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Predictor coding. The image is divided into blocks of pixels. For each block, a predictor selects the most likely value of each pixel based on its neighbors, then only the prediction error is stored. PNG also uses prediction filters, but WebP's block-based approach adapts the predictor per region rather than per scanline.
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Color space transform. WebP can transform the color space of the image before encoding to reduce entropy (randomness) in the data. Correlated color channels (common in natural images and illustrations) compress far better after this transform.
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Color cache and palette coding. Frequently occurring colors in an image are stored in a local cache and referenced by index rather than repeated in full. This is particularly effective for illustrations with a limited color palette, where the same RGB values appear in many non-contiguous regions.
Browser Support and Compatibility
WebP works in current mainstream browsers, but support in email clients, older devices, and publishing software is not identical to browser support. Check your audience and test the workflow in which the file will be used.
Chrome
Since v32 (2014)
Firefox
Since v65 (2019)
Safari
Since v14 (2020)
Edge
Since v18 (2018)
iOS Safari
Since iOS 14 (2020)
Chrome Android
Since v32 (2014)
The main compatibility gap is older email clients. Most email clients — including Outlook on Windows — do not support WebP in HTML emails. If your converted images will be used in email campaigns, keep them as PNG or JPEG. For all web and app contexts, WebP is a safe, modern choice.
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Open the EditorFrequently Asked Questions
Is WebP supported in all browsers?
WebP works in current mainstream browsers, but older software, email clients, and publishing workflows can differ. Check the audience and test the exact destination; keep a fallback where compatibility matters.
How much smaller will my WebP file be compared to the PNG?
Not necessarily. Lossless WebP can be smaller or larger than PNG depending on the image and encoder settings. Compare the real file sizes and inspect edges, transparency, and fine details before replacing the source.
Does WebP support transparency like PNG?
Yes, WebP fully supports an alpha transparency channel, both in lossless and lossy modes. Lossless WebP with transparency is a true drop-in replacement for PNG with transparency. Lossy WebP with transparency is useful for product photos with clipped backgrounds where some quality loss in the image detail is acceptable but the transparency edge must remain sharp.
Should I use WebP or AVIF?
AVIF can be a useful alternative, but relative size and quality depend on the encoder and image. Check current support for your audience and compare both formats on representative files before choosing.
Can I convert PNG to WebP for use in CSS backgrounds and img tags?
Yes. WebP works in <img> tags, CSS background-image, picture elements with srcset, and anywhere a standard image URL is accepted. For progressive enhancement, you can use <picture> with a WebP source and a PNG fallback: <picture><source srcset="image.webp" type="image/webp"><img src="image.png" alt="..."></picture>. Modern browsers will select the WebP; older ones fall back to PNG.