How to Convert PNG to WebP (Transparency Tested)

How to convert PNG to WebP: drop the file into our browser converter and set WebP as the output, or run Google's cwebp encoder from the command line. A photo saved as PNG shrinks hard as lossy WebP. A flat graphic or icon needs lossless WebP, because lossy can make that kind of file larger, not smaller.

PNG to WebP is really two conversions in one, and which you want depends on what the PNG actually holds. A photograph saved as PNG behaves like the JPG to WebP job most people already know: lossy WebP wins by a wide margin. A logo, icon, or screenshot behaves the opposite way, because WebP's lossy encoder is built to hide loss in soft photographic detail, and a flat graphic has none to give it. Mix the two up and a step meant to shrink a file hands you a bigger one instead. For where WebP and AVIF each earn their place, see the guide to WebP and AVIF. When you just need the file converted, our PNG to WebP converter handles the common case in one drop.

Why Convert PNG to WebP?

You convert PNG to WebP to cut the file size while keeping everything PNG is good at, transparency included. A lossless WebP runs about 26 percent smaller than the source PNG it came from, with the alpha channel intact, a figure both MDN and Google publish (MDN, Image file types). For a photographic PNG the saving is far bigger, because that file was carrying photo detail a lossy encoder can pack much tighter.

The size win is the practical reason, and it compounds. A PNG-heavy page is a slow page, and page weight feeds straight into both search rankings and the bounce rate you watch in analytics. If you run a store or a blog and a folder of graphics or screenshots is sitting there as PNG, converting to WebP is one of the cheapest speed improvements available, because it touches the bytes without touching the layout.

The part most converters skip is what happens to transparency, and it is the single biggest worry with a PNG. WebP keeps a full alpha channel, so a logo's see-through background comes through the conversion intact. That is not a hope, it is in the spec, and it is measured further down this page rather than asserted.

Lossy or Lossless: Match the Method to the PNG

Use lossy WebP for a photographic PNG and lossless WebP for a graphic, icon, or screenshot. That one choice decides whether the conversion shrinks the file or bloats it, and it is the mistake almost every quick converter lets you walk into.

When lossy WebP is the right call

A photographic PNG, a screenshot of a photo, or any image full of soft gradients is safe to convert with a normal lossy encode, and the savings are large. The encoder discards the fine detail your eye notices last, the same trick JPEG uses, and a photo has plenty of that detail to spare. This is the default path our browser tool takes, and for a real photo it is almost always the right one.

When only lossless WebP works

A PNG with flat color and hard edges, the kind of file a logo, icon, or line-art screenshot usually is, should go lossless or stay a PNG. Push that file through a lossy encoder and it can come back larger than it started, because the encoder spends bits smoothing edges that were never soft to begin with. Lossless WebP is the fix: it keeps every pixel exact, alpha channel included, and still lands smaller than the PNG. To convert PNG to WebP without losing quality on that kind of graphic, lossless is the only honest route, and the measured section below shows exactly how far the two paths diverge on the same file.

The transparent-pixel detail worth knowing

One quirk affects fully transparent pixels. In lossless mode, a WebP encoder is allowed to change the hidden RGB values sitting underneath a fully transparent pixel, since nothing visible depends on that color, and it does this to compress harder. Almost always this is invisible and harmless. If some later process reads the color under a transparent pixel, add the exact option to keep those values frozen.

How to Convert PNG to WebP on Any Device

There are five honest routes, and which one fits depends on whether the job is a single file or a habit. The browser tool suits one file or a quick batch, the command line suits scripts and big folders, a desktop editor suits the app you already have open, and a build pipeline suits a site that rebuilds its images on every deploy.

Convert PNG to WebP in the browser

Drop the PNG into the converter, which already has WebP set as the output, and download the result. No install, no signup for files up to 25 MB, batches up to 30 images at once, and the EXIF metadata, the hidden GPS coordinates and camera model your phone writes into a file, gets stripped on the way through. The encode runs lossy at quality 80 by default, the setting behind this site's homepage demo where a 497 KB JPG comes out a 214 KB WebP, a 56.9 percent cut with no visible change. Transparency survives that lossy path as well as a lossless one. What the browser tool does not offer is a lossless toggle, so for a graphic that has to stay pixel exact, the cwebp route below is the right tool rather than this one.

Convert PNG to WebP with cwebp, Google's command line

For a one-off file, a script, or a case the browser tool cannot cover, cwebp is the official encoder from Google's open-source libwebp package. A basic lossy encode looks like this (web.dev, Use WebP images):

cwebp photo.png -o photo.webp

For a graphic that needs every pixel to survive, add the lossless flag:

cwebp -lossless icon.png -o icon.webp

To convert a whole folder of PNGs in one pass, loop over it:

for file in images/*.png; do cwebp "$file" -o "${file%.*}.webp"; done

Set quality on the lossy path with -q from 0 to 100, and add -exact alongside -lossless when the hidden color under a transparent pixel has to stay put.

Convert PNG to WebP on Mac

To convert PNG to WebP on Mac, open the PNG in Preview, choose File then Export, and pick WebP from the Format dropdown. It is a lossy export with a quality slider, fine for a photo and not the route for a graphic that needs lossless. Preview handles one file at a time cleanly, so for a folder of images the cwebp loop above or a batch in the browser is faster.

Convert PNG to WebP on Windows

On Windows 11, Paint reads and writes WebP on current builds, so you can open the PNG and use Save as to pick WebP. Microsoft's free PowerToys adds a right-click Resize pictures option that can output WebP across several files at once, which is the closest thing Windows has to a built-in batch converter. Neither exposes a lossless switch, so treat both as the photo path.

Convert in GIMP, Photoshop, or a build pipeline

For an editor with real control, GIMP has read and written WebP since 2018 and Photoshop added WebP export in 2022; IrfanView has supported it since 2011 and Paint.NET since 2019 (PCWorld). Use Export As or Save a Copy, choose WebP, and the dialog offers the same lossy or lossless choice cwebp does, from a slider instead of a flag. For a site that regenerates its own images, the Imagemin WebP plugin drops into a Webpack, Gulp, or Grunt build in a few lines and converts every PNG that passes through, with a quality setting for the lossy path.

Convert online without installing anything

Named online tools like CloudConvert and iLoveIMG convert PNG to WebP with no install: upload, choose WebP, convert, download. They preserve transparency the way the local routes do, minus the automatic EXIF stripping, and most default to a lossy encode without exposing the lossless flag a graphic-heavy PNG actually needs. For a single quick file they are fine; for anything sensitive or repeated, a tool that keeps the file on your machine is the better habit.

Does Transparency Survive the Conversion?

Yes. Transparency survives PNG to WebP in both lossy and lossless modes, because WebP carries a full alpha channel either way (Google Developers, WebP). None of the tool pages ranking for this conversion actually prove it, so I did. I built a 512 by 512 pixel logo-style PNG with a fully transparent background and ran it through libwebp on 2026-07-17, both lossless and lossy at quality 80.

In both outputs the fully transparent corner pixel stayed fully transparent, alpha 0, and a semi-transparent edge held its exact alpha value rather than turning opaque or dropping out. The alpha channel was present in the WebP either way. So a logo, badge, or icon with a see-through background keeps that background after the conversion, in the browser tool, in cwebp, and in the editors above. The only footnote is the transparent-pixel color detail covered earlier: the visible transparency is safe, and the exact flag protects the hidden RGB values if a downstream process happens to read them.

How Much Smaller Does PNG to WebP Get?

A photographic PNG converts dramatically smaller, while a flat graphic can go either way depending on lossy versus lossless. None of the tool pages ranking for how to convert PNG to WebP put a measured number on this, so I converted two real PNGs with the encoder behind both cwebp and this site's Sharp engine, on 2026-07-17.

The first file is a 900 by 600 pixel photographic PNG with a soft transparent border.

Lossy quality 80 cut the photo to a ninth of its size and kept its transparent border, which is the result you want for anything photographic. Even the lossless path, keeping every pixel exact, came in 43 percent smaller than the PNG, well past Google's 26 percent average because this particular file was dense. Real files vary, so treat 26 percent as the floor for a lossless conversion and expect more on a busy image.

The second file is a 512 by 512 pixel flat graphic, a few solid colors on a transparent background, the kind of icon lossy WebP handles badly.

This is the reversal in one table. Lossless WebP shrank the icon by more than two thirds, while lossy quality 80 handed back a file 25 percent bigger than the PNG it started from. Google calls a PNG-to-lossless-WebP conversion a safe one and warns that pushing a few-color PNG through a lossy encoder can grow it (Google WebP FAQ); the numbers above are that warning made concrete. The takeaway is the rule from the top of the page: photo goes lossy, graphic goes lossless, and if you only have a lossy tool, leave the graphic as a PNG.

When Converting PNG to WebP Does Not Help

Skip the conversion when the destination cannot read WebP. Some older office software, a handful of print vendors' intake systems, and a few upload forms still expect a PNG specifically and will reject or mishandle a WebP. Email is the same story, since many clients render WebP inconsistently inside the message body, so an image meant to display inline in an email is safer left as a PNG or JPG.

There is also the document case. If the PNG is a diagram or screenshot bound for a Word file, a slide deck, or a print job rather than a web page, the size gain rarely outweighs PNG's universal support, and converting can break a pipeline that inspects the file for something other than how it looks. When the target is your own website, the answer is not to avoid WebP but to serve both: a <picture> element with a WebP source and a PNG fallback lets every browser take the file it can read, WebP where it is supported and the PNG everywhere else. That fallback markup belongs to your site or CMS, not to a converter, which only makes the file. And if the trip needs to run the other way, converting WebP back to PNG uses the same set of tools.