Designers argue about AVIF vs WebP the way mechanics argue about engine oil — loudly, and usually without numbers. Here are the numbers.

AVIF vs WebP: the spec table

Two rows, but they hide the biggest practical gap: file size on real images, covered next.

The kilobyte question

For AVIF, the working reality: roughly half the size of a comparable JPEG, and about 20% under WebP. For WebP: 25-34% smaller than an equivalent JPEG, per Google's published study.

Content decides everything. Flat-color graphics, screenshots and photographs sit on completely different compression curves, so the same pair of formats can swap winners between two images.

And if the destination is a web page, keep the modern baseline in view: WebP runs 25-34% under JPEG and AVIF roughly halves it — sometimes the right answer to "AVIF or WebP" is a third format entirely.

Whichever way the kilobytes fall, remember they compound: a saving of 200 KB per image across a forty-image page is eight megabytes a visitor never downloads.

What each format can carry

AVIF is lossy and lossless, strongest at next-generation web images, high-quality compression; its known costs are slower encoding, limited browser support in older versions.

WebP is lossy and lossless, aimed at modern websites, web optimization, progressive web apps; the trade-off there: not supported in older browsers, limited editing software support.

Neither list is a flaw — formats are tools, and a hammer is not a bad screwdriver. The question is only which job sits on your desk.

Which one should you use?

Choose AVIF when your job looks like next-generation web images, high-quality compression and the priority is 50% smaller than JPEG, HDR support, excellent quality.

Choose WebP when you are in modern websites, web optimization, progressive web apps territory and need 25-35% smaller than JPEG, supports transparency and animation.

Switching sides costs nothing: the WebP converter and the AVIF converter each take seconds, so test both on a real file from your project.

Converting between AVIF and WebP

Moving a file either way is the easy part: the WebP converter and the AVIF converter both take drag-and-drop batches and return a ZIP. Dimensions never change; only the encoding does.

Convert once from the best source you have — chaining a file through three formats is how visible artifacts are born.

Thirty seconds of compression theory

Dual-mode formats carry both toolboxes: a lossy mode for photographs and a lossless one for graphics. That flexibility is exactly why the modern web formats displaced single-mode ancestors.

Once you see the mechanism, every size difference in this article stops being magic and starts being arithmetic.

When something looks wrong

Colors shifted. Wide-gamut originals viewed in sRGB-only software look washed out. The fix is converting from an sRGB copy for web use — not a higher quality setting.

The file will not open. Nine times out of ten the viewer is the limitation, not the file. Try a second viewer before blaming the conversion, or convert to WebP — if that copy opens, the original was fine all along.

Transparent areas turned white. The target format has no alpha channel; flattening is the documented behaviour, not a bug. Re-convert to PNG or WebP if transparency must survive.

The file got bigger. Some content genuinely compresses worse in the new format — flat graphics in photo-oriented codecs, photos in graphics-oriented ones. The size readout before download is the early warning.

The history that explains the gap

AVIF comes from 2019, built by the Alliance for Open Media; WebP from 2010, by Google. Every difference in the table above traces back to what problems were worth solving in those two moments.

The general law of image formats: the older one opens in more places, the newer one wastes fewer bytes. AVIF and WebP follow it exactly.

Who picks what, in practice

The photographer delivering a wedding gallery cares about quality first and upload time second — the format whose profile reads "50% smaller than JPEG, HDR support, excellent quality" or "25-35% smaller than JPEG, supports transparency and animation" closer to that wins the job.

The web developer chasing Core Web Vitals weighs file size above everything: between roughly half the size of a comparable JPEG, and about 20% under WebP and 25-34% smaller than an equivalent JPEG, per Google's published study, the smaller real-world output gets shipped.

The office user attaching a file for an unknown recipient optimizes for one thing — that it opens. Whichever of the two enjoys broader support is the safe envelope.

The print shop reverses every web instinct: resolution and lossless data outrank file size completely, because a 60 MB master is cheaper than a reprint.

Transparency, animation and the small print

Transparency: AVIF carries an alpha channel; WebP supports it. If your work involves logos over photos or UI elements, this single row outweighs every compression argument.

Animation: AVIF can animate; WebP can animate.

Both formats are exactly as old as their trade-offs suggest: AVIF from 2019, WebP from 2010.

The Core Web Vitals angle

Images are usually the heaviest asset class on a page, so format choice flows straight into Largest Contentful Paint — the Core Web Vitals metric Google weighs for ranking. Lighter images, earlier paint, better scores: the chain is that direct.

Pair the format change with loading="lazy" on below-the-fold images and correct display dimensions, and the speed gain typically doubles.

Measure before and after with PageSpeed Insights — the image-weight line item makes the improvement concrete instead of theoretical.

Workflow and software support

AVIF is handled by effectively every editor of its generation: support in 2026 means over 93% of browsers in 2026, including Chrome, Firefox, Safari and Edge.

For WebP, the picture is over 96% of browsers in use in 2026 (caniuse). That difference decides more real projects than any quality argument does.

Quick Answers

Which is smaller, AVIF or WebP?

Depends on the image. The anchors: for AVIF, roughly half the size of a comparable JPEG, and about 20% under WebP; for WebP, 25-34% smaller than an equivalent JPEG, per Google's published study. Photographs and flat graphics compress on opposite curves, so test one of your own files rather than trusting an average.

Can I convert between AVIF and WebP without quality loss?

Lossless-to-lossless conversions are perfect copies. The moment a lossy format is involved, some data is discarded — normally invisible at default settings, but keep your originals as the master copies.

Which should I send to a print shop?

Print workflows want lossless, high-resolution files — that points to formats like TIFF and PNG. Between these two, the one with WebP's compression profile is the safer print choice.

Can I serve both formats on the same website?

Yes — the HTML picture element exists for exactly this: list the efficient format first and the compatible one as fallback, and each browser takes the best it understands. It is the standard pattern on image-heavy sites.

Do AVIF and WebP support animation?

AVIF: yes. WebP: yes. For short animated clips on the web, animated WebP has largely replaced the older approaches on size alone.

Can I batch convert a mixed folder of AVIF and WebP?

Yes — converters key on each file's actual type, not the folder. Drop the mixed set, pick one target format, and the output comes back uniform in a single ZIP.

Written by Giovanni Picaro, a web developer who has been building image tools and optimizing sites since 2019. Sources: MDN image format reference and Google web.dev. Last reviewed: 2026.