WebP Converter

WebP is a genuinely newer codec, built around prediction techniques developed for video compression rather than the 1990s-era discrete cosine transform JPEG still uses. Its lossy mode predicts each block of pixels from the blocks already decoded around it before encoding only the difference, which captures far less redundant data than JPEG's independent per-block encoding — and it is this prediction step, more than any single parameter, that accounts for most of the size advantage.

WebP also does something JPEG and PNG cannot do individually: it supports both lossy and lossless compression, plus a full alpha channel, in one format. That means a single codec now covers what used to require choosing between JPEG (small, no transparency) and PNG (transparency, much larger for photographic content) — WebP's lossy mode handles photographs with transparency at a fraction of PNG's size, something neither older format can do.

Beyond the lossy mode most conversions use, WebP also has a lossless mode that competes directly with PNG rather than with JPEG — same pixel-perfect guarantee, typically 20–30% smaller than PNG for the same image. It exists for the same content PNG is used for: screenshots, logos, flat graphics, anything where discarding data is not acceptable. This converter defaults to lossy output because most conversions are for photographic content where a small, invisible quality reduction is the better trade, but the underlying format supports both.

The saving from switching to WebP compounds across an entire page rather than showing up on one file at a time — a page with a dozen images each 30% smaller adds up to a meaningfully lighter total page weight, which is the kind of change that actually moves a Core Web Vitals score, particularly Largest Contentful Paint on image-heavy pages. This is why WebP adoption has been driven largely by sites optimising for page speed rather than by any single dramatic before-and-after comparison on one image.

Every browser in current use — Chrome, Firefox, Safari, Edge, and their mobile equivalents — has supported WebP for several years, so for anything displayed on a web page, compatibility is no longer a real concern. The caveat is software outside the browser: some older desktop image viewers, some version of Windows' built-in preview before recent updates, and a fair amount of print and design software still cannot open a WebP file directly.

The practical rule that follows: convert to WebP freely for anything that only needs to display on a web page, and keep a JPEG or PNG original for anything that might be opened, edited, emailed as an attachment, or handed to someone whose software is unknown. Web servers commonly serve WebP with a JPEG fallback for exactly this reason, using the `picture` element to let the browser choose.