PNG to WebP Converter
Lighter website assets: PNG to WebP, lossless or lossy, with transparency kept.
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About the PNG to WebP Converter
Convert PNG images — screenshots, logos, icons, illustrations and anything with transparency — to WebP, the format all current browsers use for lighter pages. Choose Lossless for a pixel-identical copy, or Lossy with separate quality settings for the colours and for the transparency (alpha channel).
Each file shows the size change against its PNG. WebP is not always smaller — tiny icons and PNGs that were already squeezed with a palette sometimes come out larger — so those files are flagged, and you can leave them out of the ZIP. PNGs are decoded exactly (no browser colour rounding), encoded with Google’s libwebp in your browser, and an embedded colour profile is carried over.
How to use it
- Drop PNG files onto the box, click Choose PNG images, or paste a screenshot with Ctrl/⌘ + V.
- Pick Lossless (identical pixels) or Lossy; for lossy, set the Quality and the Alpha quality for transparent areas.
- Check the size change on each file. Files marked “WebP is larger” are better kept as PNG — tick Leave out files that get bigger to skip them in the ZIP.
- Download each WebP, or Download all as a ZIP for your website or app.
Examples
settings.png · 2560 × 1600 · Lossless
settings.webp with exactly the same pixels, usually noticeably smaller than the PNG.
bag.png (transparent, 1500 × 1500) · Lossy · Quality 80 · Alpha 90
bag.webp with transparency, typically a fraction of the PNG size; the shadow stays smooth.
icon.png (already optimised, 400 bytes) · Lossless
Flagged if the WebP is not smaller — keep the PNG for this one.
Common uses
- Making website images, theme assets and blog screenshots load faster.
- Converting transparent logos and product cut-outs for online shops.
- Preparing app and game assets where WebP is supported.
- Checking which of your PNGs actually benefit from WebP before replacing them.
Lossless or lossy?
WebP (documented by the IETF in RFC 9649) has two compression modes, and both support transparency:
- Lossless keeps every pixel — colour and transparency — exactly as in the PNG, including the hidden colour values under fully transparent pixels (libwebp’s exact mode). Google reports lossless WebP files are 26% smaller than PNGs on average (WebP overview). Best for screenshots, text, line art and pixel art.
- Lossy compresses like JPG but keeps transparency. Google reports that lossy WebP with transparency is typically about three times smaller than PNG. Best for photos, cut-outs and illustrations with gradients.
What does alpha quality do?
In lossy WebP the transparency is stored separately from the colours. Alpha quality 100 keeps it lossless — edges, soft shadows and glows stay exact — while lower values let libwebp simplify the transparency for smaller files. Values of 80–100 look the same for most images; lower values can make soft edges look banded. It has no effect on images without transparency.
Why can a WebP be larger than the PNG?
PNG and WebP compress in different ways. Very small images (where the file header is a big part of the size), images saved as 8-bit palette PNGs by an optimiser, and lossless conversions of noisy photos can end up the same size or larger. This converter compares every file and marks those cases, so you only replace PNGs that really get lighter. Smaller files (slower) lets libwebp try harder, which often wins back a few percent.
Limitations
- Up to 100 files per batch, each up to 200 MB and 50 megapixels.
- Animated PNGs (APNG) are converted to their still image — normally the first frame; the animation is not kept. WebP stores 8 bits per channel, so 16-bit PNGs are reduced to 8 bits.
- Text and EXIF metadata in the PNG are not copied; an ICC colour profile is.
- Encoding uses WebAssembly in every browser (needed for the alpha-quality and exact-pixel options), so very large images take a few seconds.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
Is lossless PNG to WebP really identical?
Yes, for ordinary 8-bit PNGs. In Lossless mode the PNG is decoded exactly and encoded with libwebp’s lossless exact mode, so every pixel’s red, green, blue and alpha values are the same in the WebP — you can convert it back to PNG with WebP to PNG and get the same pixels. A 16-bit PNG is first reduced to 8 bits per channel, the most WebP can store; the file is marked when that happens.
Will my transparent background stay transparent?
Yes, in both modes. Lossy WebP stores transparency separately; keep Alpha quality at 90–100 for clean edges.
Which quality should I use for lossy?
75–85 suits most photos and illustrations. For graphics with text or sharp lines, lossless is usually better and often smaller.
Do all browsers support WebP with transparency?
Yes — current Chrome, Edge, Firefox, Safari and Opera display WebP, with and without transparency.
Are my images uploaded?
No. Decoding and encoding run in your browser, and the page works offline once loaded.