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PNG to WebP Converter

Convert a PNG to a much smaller WebP in your browser, keeping transparency, at 92% quality.

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Quick answer

PNG to WebP re-encodes your PNG as a WebP image on an HTML5 canvas, in your browser. WebP keeps the PNG's transparency and compresses far more efficiently: Google measures lossy WebP at 25-34% smaller than JPEG and roughly 3x smaller than a transparent PNG. This tool encodes at 92% quality (lossy) and keeps the dimensions. Your image stays on your device. If a browser cannot encode WebP, the download falls back to PNG.

  • 92%WebP quality
  • Kepttransparency
  • ~3x smallerthan a transparent PNG (Google)
  • 0files uploaded

What the PNG to WebP Converter does

PNG is lossless and, for photos or rich graphics, often heavy. Google built WebP to compress much harder while still supporting transparency, which is why it is the usual choice for fast-loading web images.

This tool re-encodes your PNG as WebP and keeps any alpha channel. The output is lossy at 92% quality, so it looks very close to the original at a far smaller size, the normal trade for web delivery.

How it works

Your PNG is decoded and drawn onto an HTML5 canvas at full size, transparency included. The canvas gets no white fill, because WebP supports alpha and see-through areas can stay see-through.

The canvas is exported as WebP at quality 0.92 by the browser's own encoder. If a browser does not support WebP encoding, the canvas standard falls back to PNG, so the saved file would be a PNG.

Where the transparency goes

PNGcanvas, no fillWebPalpha kept
The canvas gets no background fill, so see-through areas stay see-through in the WebP.

Processing pipeline

  1. Step 1. Drop in a PNG (any common image works). It is decoded locally.
  2. Step 2. A canvas is created at the image's exact size, keeping any transparency.
  3. Step 3. The image is drawn and encoded as WebP at 92% quality (lossy).
  4. Step 4. Most browsers encode WebP natively; if one cannot, the output falls back to PNG.
  5. Step 5. The .webp downloads with your original filename and the same dimensions.

Privacy

The conversion runs on your device: the PNG is drawn and re-encoded in the page's memory and the WebP is produced locally, so no server ever holds a copy.

Once you close the tab, neither the PNG nor the WebP remains anywhere, which makes the tool safe for unreleased logos and other private assets.

Technical details

EngineHTML5 Canvas (browser-native)
OutputWebP (.webp)
Quality92% (0.92), lossy
TransparencyPreserved (WebP supports alpha)
Size vs PNGMuch smaller, up to ~3x on transparent images
DimensionsUnchanged (same width by height)
FallbackPNG, if the browser cannot encode WebP

Standards and references

  • PNG (ISO/IEC 15948): the lossless source format: DEFLATE-compressed, with an optional alpha channel that WebP can also keep.
  • WebP (Google): the target format, built on VP8/VP8L; supports lossy, lossless, and transparency, and compresses more efficiently than PNG or JPEG.
  • HTML Canvas API: toBlob('image/webp', 0.92) encodes WebP in the browser; if WebP is not supported it falls back to PNG per the spec.

Accuracy and limits

The output is lossy. At 92% quality the difference from the PNG is hard to spot, but fine detail is compressed and the copy is not pixel-perfect. If you need lossless, keep the PNG.

The savings are often large. Google measures lossy WebP at 25-34% smaller than JPEG, and lossy WebP with transparency at roughly 3x smaller than PNG, so a heavy transparent PNG can shrink a lot.

Transparency is preserved because the canvas is not flattened, so the PNG's alpha channel carries into the WebP. Converting to JPEG instead would force a solid background.

Encoder support varies. Chrome, Edge, Firefox and Opera encode WebP from the canvas; where a browser cannot, the canvas API falls back to PNG, so check that your download really is a .webp. Output bytes can differ slightly between browsers, since each ships its own encoder.

How much smaller, by Google's figures

transparent PNGlossy WebP with alphaabout 3x smaller
That's Google's average. Flat graphics that are already small as PNG may barely shrink.

Real-world uses

Faster-loading web images

Replace heavy PNGs with WebP to cut page weight while keeping transparency.

Transparent graphics, smaller

Shrink a cut-out logo or icon that needs its alpha channel.

Save storage or bandwidth

Keep images that look the same at a fraction of the PNG size.

Modern asset pipelines

Produce WebP for sites and apps that serve next-gen formats.

When it fits, and when it doesn't

Good for

  • Web images that must stay small
  • Keeping transparency at a smaller size
  • Replacing heavy PNGs
  • Sites and apps that support WebP

Not the best choice for

  • A lossless master copy
  • Targets that only accept PNG/JPEG
  • Tiny flat graphics already small as PNG
  • Archival originals

Need lossless or universal compatibility? Keep the PNG. Need a photo small without transparency? PNG to JPG may compress a touch more.

Frequently asked questions

Does WebP keep my PNG's transparency?
Yes. WebP supports an alpha channel and the tool does not flatten the image, so transparent areas stay transparent. Converting to JPEG would fill them with white.
How much smaller is the WebP?
Often a lot. Google measures lossy WebP as 25-34% smaller than JPEG and lossy transparent WebP as roughly 3x smaller than PNG, so heavy PNGs can shrink dramatically.
Is the WebP lossy or lossless?
Lossy, encoded at 92% quality. It looks very close to the original but is not pixel-identical. For a lossless file, keep the PNG.
Why did my download come out as a PNG?
Some browsers cannot encode WebP from a canvas. When that happens, the canvas standard falls back to PNG, so the saved file is a PNG. Chrome, Edge, Firefox, and Opera support WebP encoding.
Are my files uploaded?
No. The PNG is decoded and re-encoded on an HTML5 canvas in your browser. Nothing goes to a server, and refreshing clears it from memory.
Do the dimensions change?
No. The WebP keeps the PNG's exact width and height. The smaller size comes from WebP compression, not resizing.
Will every browser open the WebP I create?
For viewing, yes: all modern browsers decode WebP. Compatibility matters mainly with older desktop apps and some upload forms, where PNG or JPEG is safer.
Can I convert a JPG to WebP here too?
Yes. It accepts any image the browser can open and outputs WebP. A JPG has no transparency to keep, but it will still re-encode to a smaller WebP.
Is my original PNG changed?
No. A new .webp (or PNG, on a fallback) is created and your PNG is left untouched.
Does it work on a phone?
Yes, in any modern mobile browser that supports WebP encoding. Larger images use more memory while encoding.

References

Written from the tool's own WebP encode call (quality 0.92), including the PNG fallback some browsers trigger.

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