PNG to WebP: how much smaller do your images actually get?

If your site is still shipping PNGs, you're probably serving images two to four times larger than they need to be. WebP was built specifically to fix this—and the size difference is easy to see and measure for yourself.

Here's what actually changes when you convert, when it doesn't matter, and when you should leave a PNG exactly as it is.

The short answer

Converting a lossless PNG to lossless WebP typically saves 25–35% in file size with zero visible quality loss. Switch to WebP's lossy mode and you're looking at 50–80% smaller, often with quality that remains indistinguishable at normal viewing sizes.

Why WebP is smaller in the first place

PNG was designed in 1996 for lossless compression of web graphics. It is dependable and widely supported, but it was never the smallest option. WebP supports lossless and lossy compression in one format, along with:

• Alpha transparency: logos and icons retain transparent and soft edges.
• Better lossless compression: WebP removes more redundant image data.
• Optional lossy mode: trade a small amount of quality for much larger savings.
• Animation: frame timing and transparency can be preserved.

WebP takes marginally more CPU power to decode than PNG, but this is not noticeable on a typical device from the last decade.

Real numbers: what to expect by image type

Photo-like images with gradients and fine detail see the largest gains because PNG is not efficient at compressing them. Flat graphics with few colours start smaller, so their percentage savings are usually lower.

Does WebP keep transparency?

Yes. WebP supports alpha-channel transparency, so semi-transparent pixels, soft shadow edges, and fully transparent backgrounds carry over from the source PNG. It is a direct replacement for most transparent logos, icons, and interface graphics.

When you should still use PNG

WebP is a strong default, but PNG still makes sense when:

• You need compatibility with legacy software, editors, or CMS platforms.
• You are preserving a source-of-truth master file for future editing.
• A print workflow, email client, or API explicitly requires PNG.

For browser-rendered website images and application assets, WebP usually wins.

Browser support in 2026

Chrome, Firefox, Safari, and Edge support WebP. If your audience still needs a PNG fallback, use the HTML <picture> element:

<picture>
  <source srcSet="logo.webp" type="image/webp" />
  <img src="logo.png" alt="Logo" />
</picture>

Why this matters for SEO and Core Web Vitals

Image weight directly affects page speed. Largest Contentful Paint is frequently a hero image, so reducing that asset from 1.2 MB to 200 KB can materially improve the experience before you change anything else.

PageSpeed Insights and Lighthouse also identify opportunities to serve images in modern formats. Converting suitable PNG files addresses that recommendation directly.

How to convert PNG to WebP

Go from a heavy PNG to a production-ready WebP in four simple steps.

1. 01Open the converterLaunch the PNG to WebP workspace—no account or setup required.
2. 02Choose your PNGDrag and drop the image or browse for it from your device.
3. 03ConvertThe converter encodes the image on our server, in memory, and returns the WebP.
4. 04Download and replaceSave the smaller WebP and use it in the same place as the original PNG.