NiftyWebTools Compress a PDF

Image tool

PNG to WebP

Convert PNG to WebP in your browser, up to 50 at a time, with a quality slider and transparency kept. Files stay on your device.

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How to use it

How to use PNG to WebP Converter

  1. Drop your PNG files onto the workspace, paste from the clipboard, or pick them with the file picker. Up to 50 images per batch, 100 MB per file.
  2. Adjust the quality slider if you want — default 80 is a practical web-delivery starting point; tune higher for visual fidelity or lower for smaller files.
  3. Click Convert. Each image decodes through the browser's built-in PNG path, draws into an alpha-aware canvas, and re-encodes as WebP through `canvas.toBlob('image/webp', q)`. Safari does not currently implement that encoder and silently returns a PNG (per the HTML spec's fallback rule). The tool detects the non-WebP MIME on the returned blob and surfaces a clear error rather than writing a misnamed `.webp` file — switch to a current Chrome, Edge, or Firefox to encode WebP. Download individually or grab the whole batch as a single ZIP.

Good for

Common use cases

PNG is a lossless format for screenshots, interface graphics, transparent logos, charts and diagrams. WebP supports lossy compression and keeps an alpha channel. Use this converter when you want to test a lighter web copy without removing transparency. It suits documentation screenshots, product cut-outs, dashboard images and blog graphics. The size change depends on the source pixels and quality setting. Some files shrink, while others change very little. Lossy WebP can also soften text, lines and small interface details. Check the preview at the size visitors will see before publishing. Keep PNG when you need a lossless source, print output or broad software compatibility. You can serve WebP through a `<picture>` element and keep PNG as the fallback. The conversion runs in your browser, so the source stays on your device. You can process a batch, inspect each image and download separate files or one ZIP. This local workflow helps with unreleased interface designs, private dashboards and licensed artwork that should not reach a conversion server.

Privacy

Runs in your browser

Files are processed by your browser. They never reach our servers.

Questions

PNG to WebP Converter: common questions

Should I convert PNG to WebP for everything?

No. WebP is for web delivery — assets you serve from your own site, CMS, or CDN, where you control the response and can pair a `<picture>` fallback for any browser that cannot decode WebP. It is the wrong target for print pipelines, marketplace listings (Etsy lists `.jpg`, `.gif`, `.png`, `.svg`, and `.heic` as accepted product images, with no WebP in the list), older or locked-down Office installs that may render WebP as a broken-image placeholder, and email attachments where the recipient's reader may not decode WebP. Use PNG when the destination is unknown, compatibility-sensitive, or genuinely needs lossless fidelity (architectural diagrams, design source files, archival masters); use WebP when you control the delivery and the goal is performance.

Does the WebP keep the PNG's transparency?

Yes. WebP supports alpha channels in both its lossy and lossless modes, and the Canvas `toBlob('image/webp', …)` path preserves the alpha through the encode. Transparent regions in the source PNG come through as transparent regions in the output WebP, so a transparent logo, a rounded-corner avatar, or a product cutout against a page background renders identically once swapped in. There is no flatten-to-white step, no black-fill artefact, and no need to reach for a separate converter when the asset has alpha — that is the structural difference between this tool and JPG-to-WebP, where the destination format does not support alpha at all.

Is the conversion lossless or lossy?

The Canvas WebP encoder runs in lossy mode at the quality you choose. WebP also has a lossless mode, but this tool does not use it. Lossy WebP can reduce file size, but it changes pixel data. Keep the PNG when you need lossless source material.

How much smaller are WebP files compared to PNG?

The result depends on the image and quality setting. Screenshots, small icons and photographs can all respond differently to conversion. Pair the WebP with a PNG fallback when your audience may use software that cannot decode WebP.

Which browsers can run this WebP encoder?

Canvas WebP encoding through `canvas.toBlob('image/webp', quality)` is supported in current Chrome (since version 50, April 2016), Edge (since the Chromium switch at version 79, January 2020), and Firefox (since version 96, December 2021). Safari does not currently implement the Canvas WebP encoder. Safari renders WebP images via `<img>` perfectly well, but `canvas.toBlob('image/webp', …)` returns a PNG instead — that is the HTML spec's mandated fallback when the requested MIME type is unsupported. The tool detects the non-WebP MIME on the returned blob and surfaces a clear error rather than writing a `.webp` file that is actually a misnamed PNG. The fix is to switch to a current Chrome, Edge, or Firefox.

Is there a file size or batch limit?

Each PNG must be under 100 MB and a single batch can hold up to 50 images. The 100 MB cap protects lower-RAM devices from running out of memory during decode, since the browser materialises the full pixel grid into a canvas before re-encoding. The 50-file cap keeps the ZIP build responsive — for large batches the bottleneck is browser memory, not the conversion itself, since each image processes sequentially. If you need to convert more than 50 images, run the tool twice and stack the resulting ZIPs — the conversion is deterministic, so the second batch produces output identical to what one continuous run would have written.

Will this tool stay free?

Yes. Everything this tool does is free. On some tools, a Day or Project Pass raises the file-size and batch limits if you need more.