PNG to WebP Converter

PNG is a lossless format built in 1996 around a compression method called DEFLATE. It stores every pixel exactly, which makes it ideal for screenshots, logos, and graphics with hard edges — and makes the files large, because lossless compression can only do so much with a detailed image.

WebP, developed by Google, offers both a lossless mode and a lossy mode in a single format. Its lossless mode uses smarter techniques than PNG: it predicts pixel values from neighbouring pixels, reuses repeated colour patterns through a palette cache, and applies more efficient entropy coding. The result looks identical but is meaningfully smaller.

The lossy mode goes further by discarding visual information the eye is unlikely to notice — the same broad idea JPG uses, except WebP keeps the alpha channel while doing it, something JPG has never been able to do. That combination of transparency plus lossy compression is the main reason PNG to WebP conversion produces such large savings on web graphics.

This is the question most people have before converting, so it is worth being precise: WebP supports a full 8-bit alpha channel, giving 256 levels of transparency per pixel. That is the same depth PNG-24 provides. A logo on a transparent background, a product cutout with a soft drop shadow, or an icon with anti-aliased curves will all convert without a visible halo or hard fringe.

Where transparency can degrade is at very aggressive compression settings on images with fine semi-transparent detail — think smoke, glass, or feathered edges over a busy background. If your PNG falls into that category, use Best Quality mode and check the preview before downloading. For everything else, the default settings handle alpha cleanly.

Google's own benchmarks put lossless WebP at roughly 26% smaller than PNG across a large test corpus. That figure is the conservative case — it assumes you want a pixel-perfect copy. In real use the savings are usually far larger, because most PNGs on the web do not need to be lossless at all.

A 1920px application screenshot saved as PNG-24 commonly lands between 400KB and 1.5MB. Converted to lossy WebP at a sensible quality level, the same screenshot typically comes out between 40KB and 120KB while remaining perfectly readable. Flat graphics — charts, diagrams, illustrations with large single-colour regions — compress hardest of all, often dropping more than 80%.

Photographic PNGs behave differently. If a camera photo was exported as PNG, the file is enormous for no benefit, and converting it to WebP produces the most dramatic reduction this tool will show you — frequently a tenth of the original size.