WebP

WebP is an image format developed by Google in 2010 and standardised in 2018. Supports lossy and lossless compression in the same format, full alpha (transparency), and animation. Compresses 25-35% smaller than JPG at equivalent visual quality.

Browser support as of 2026: ~97% globally. Safari was the last major holdout, adding WebP in version 14 (September 2020). The remaining 3% are old Android versions, IE11 stragglers, and embedded browsers.

WebP’s lossy mode is based on VP8 (Google’s open video codec, used by WebM video). It uses block-prediction-and-transform similar to H.264, applied to a single frame. The result: meaningfully better compression than JPG’s 1992-era DCT.

Practical use:

• For new web content: WebP first, JPG fallback via <picture>.
• For replacing existing JPGs: easy 25-35% size reduction, no quality regression.
• For replacing PNGs with alpha: WebP lossless + alpha is dramatically smaller than PNG (often 30-50% the size).
• vs AVIF: AVIF is even smaller (~20% smaller than WebP at equivalent quality) but encodes 10-100× slower and has narrower browser support (~93% in 2026). WebP is the safer default.

Convert any image to WebP in your browser via our image converters.

The On2 acquisition story — why WebP exists: Google acquired On2 Technologies in February 2010 specifically for the VP8 video codec, then released VP8 as open-source under a permissive BSD-style licence. WebP was announced eight months later as a still-image format derived from a single VP8 keyframe. The acquisition price was $124.6M — paid in part to provide a patent-clean alternative to HEIF/HEIC, whose licensing pool was incompatible with browser-wide deployment. The same strategic logic produced VP9, AV1, and eventually AVIF.

The quality-knob asymmetry: WebP’s lossy quality slider runs 0-100 like JPG’s, but the curves are different — quality 80 in WebP is visually equivalent to roughly quality 90 in JPG at a noticeably smaller file size. The lossless WebP encoder ignores the quality flag entirely; instead, a -m method parameter (0-6) trades encoding time for tighter compression. Tools like cwebp (the reference encoder), sharp (Node.js), and squoosh (browser) all expose these settings. For automated build pipelines, quality 75-80 lossy is the typical sweet spot; for icons and graphics where alpha matters, lossless with method 6 is the sweet spot. Related: AVIF, lossless, lossy. Reference: Google — WebP, A new image format for the Web.

Worked example

Take a 1920×1080 hero photo, originally a 480 KB JPG at quality 85. Convert to WebP at quality 80 with cwebp: cwebp -q 80 hero.jpg -o hero.webp → ~320 KB, a 33% reduction at visually-indistinguishable quality. Convert the same source to a lossless PNG: ~3.2 MB. Now imagine the same source needs an alpha-channel cutout for a product render. Save as PNG-24 with alpha: ~1.8 MB. Save as lossless WebP: ~650 KB (a 64% reduction). Across a typical e-commerce page with 30 product images, swapping JPG/PNG sources to WebP can cut the image payload from ~6 MB to ~3 MB — directly improving LCP (Largest Contentful Paint) by 1-2 seconds on a 3G connection, which feeds directly into Core Web Vitals and SEO ranking.

When and why it matters

Image payload is typically the largest single contributor to mobile-page weight, and Core Web Vitals (LCP specifically) is a documented Google ranking factor. The cheapest performance optimisation for any image-heavy site is to add a <picture> element with WebP and AVIF sources alongside JPG fallbacks — modern Next.js (next/image), Astro, Eleventy, and Nuxt do this automatically. The handful of situations where WebP isn’t the right answer: when the asset will be edited downstream (use a lossless master), when the target audience is on browsers that don’t support it (very old Android, certain embedded webviews — provide JPG/PNG fallback), and when the image is a photograph for print (use TIFF or the original RAW). For everything else served to a modern web browser in 2026, WebP-or-AVIF should be the default and JPG a legacy fallback. Reference: web.dev — Serve images in WebP formats.