Quick Answer
AVIF compresses images better than any other common format today, with files about 20% smaller than WebP at the same quality. WebP has wider browser support and encodes much faster. Use AVIF when file size is critical and your audience uses modern browsers, and use WebP as the default.
AVIF vs WebP Comparison
| Feature | AVIF | WebP |
|---|---|---|
| Compression | AV1 (most efficient) | VP8 |
| File size | ~20% smaller than WebP | Larger than AVIF |
| Quality | Best at equivalent size | Very good |
| Transparency | Yes (alpha channel) | Yes (alpha channel) |
| Animation | Yes (AVIF sequences) | Yes (animated WebP) |
| Browser support | ~92% (Chrome 85+, Safari 16.4+) | ~97%+ (all modern browsers) |
| Encoding speed | Very slow (10-50x WebP) | Fast |
| Decoding speed | Comparable | Fast |
| HDR support | Yes | Limited |
| Color space | Wide gamut (BT.2020) | sRGB, limited wide gamut |
| Best for | Maximum compression | Broad compatibility + performance |
When to Use AVIF
- Sites where every kilobyte counts toward performance metrics
- High-resolution images, where the savings grow with image size
- Progressive enhancement: serve AVIF to browsers that support it and WebP as the fallback
- HDR photography, since AVIF supports high dynamic range content natively
- Mobile-first audiences on slow connections, where bandwidth is limited
- Static image libraries that are encoded once and served many times, so slow encoding is acceptable
When to Use WebP
- As the default web format, the safest modern choice for any website
- Dynamic image generation, because fast encoding suits real-time or on-the-fly conversion
- Pages that need the broadest compatibility, since WebP works in virtually all modern browsers
- Animated content, which has better tooling and faster encoding in WebP
- CMS and platforms, as most content management systems handle WebP natively
- Quick batch processing, where encoding speed matters because many images are converted
The Encoding Speed Problem
Encoding speed is AVIF's biggest drawback. A single high-resolution photo can take 10-50x longer to encode as AVIF than as WebP:
- A 4K photo to WebP: ~1-2 seconds
- A 4K photo to AVIF: ~10-50 seconds
The difference shows up in:
- Real-time user uploads, where the wait affects the experience
- CI/CD pipelines, where build time increases
- Batch processing of large image libraries
- Dynamic image resizing services
For static assets that are encoded once and cached, the slower speed is less of a concern.
Serving Both Formats
To get both compatibility and small files, serve both formats with HTML's picture element:
<picture>
<source srcset="photo.avif" type="image/avif">
<source srcset="photo.webp" type="image/webp">
<img src="photo.jpg" alt="Description">
</picture>Browsers that support AVIF get AVIF, the rest get WebP, and JPG is the final fallback. Most modern build tools and CDNs can automate this.
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Convert images to AVIF or WebP in your browser, with no software to install.