WebP vs AVIF: Which Format Should You Use in 2025?

Introduction

The debate between WebP and AVIF has become increasingly relevant as website performance and user experience continue to be critical factors in web development. Both formats promise significant improvements over traditional JPEG and PNG, but they take different approaches to achieving compression and quality.

WebP, developed by Google and released in 2010, has had over a decade to mature and gain adoption. AVIF (AV1 Image File Format), based on the AV1 video codec, arrived in 2019 and represents the newest generation of image compression technology.

In 2025, both formats enjoy strong browser support, robust tooling, and widespread adoption. So which one should you choose for your projects? Let's dive into a comprehensive comparison.

Compression Comparison

File Size Efficiency

AVIF consistently achieves better compression than WebP, typically producing files 20-50% smaller than equivalent-quality WebP images. This advantage is most pronounced with photographic content and complex images with gradients.

For example, a 1920×1080 photograph that's 850KB as a JPEG might compress to:

• WebP: ~300KB (65% reduction from JPEG)
• AVIF: ~180KB (79% reduction from JPEG, 40% smaller than WebP)

However, the compression advantage of AVIF diminishes with certain content types. For graphics with solid colors, text overlays, or simple illustrations, WebP and AVIF perform more similarly, with differences often under 10-15%.

Quality at High Compression

AVIF's superior codec allows it to maintain better visual quality at aggressive compression levels. At very small file sizes, WebP images tend to show more artifacts, particularly in areas with fine detail or texture. AVIF handles these scenarios more gracefully.

This makes AVIF particularly attractive for mobile-first websites where bandwidth is precious and users are on metered connections.

Lossless Compression

Both formats support lossless compression, though this is rarely used in production due to the large file sizes. When lossless compression is needed:

• WebP lossless: Typically 25-30% smaller than PNG
• AVIF lossless: Typically 40-50% smaller than PNG

For most web use cases, PNG remains the preferred lossless format due to universal support and simpler workflows.

Visual Quality Comparison

Photographic Images

AVIF excels with photographic content. Its advanced perceptual modeling produces images that look sharper and more detailed at equivalent file sizes. Color gradients (like skies or skin tones) appear smoother, with less banding.

WebP is no slouch — it still produces excellent results for photos. But in direct side-by-side comparisons at similar file sizes, most observers prefer AVIF's rendering.

Graphics and UI Elements

For graphics with sharp edges, text, or logos, both formats perform well. WebP has a slight edge in encoding speed for this content type, while AVIF sometimes produces marginally smaller files.

For web UI components, icons, and graphics, the visual differences are often imperceptible. File size differences are minimal, so encoding speed becomes a more important factor (where WebP wins).

Transparency and Alpha Channels

Both formats support transparency. AVIF's alpha channel compression is more efficient, resulting in smaller files for images with transparency. However, WebP's alpha implementation is more mature and widely tested across various rendering engines.

Browser Support in 2025

Global Support in 2025:

• WebP: 96.5% of all users (Can I Use data)
• AVIF: 89.2% of all users (Can I Use data)

WebP has near-universal support. The remaining 3.5% is primarily older Safari versions and niche browsers. AVIF's support has grown rapidly — the main holdouts are users on iOS 15 and older, and people running outdated browsers.

For most modern websites in 2025, both formats can be used safely with JPEG fallbacks for the small percentage of unsupported browsers.

Encoding and Decoding Speed

Encoding Speed

WebP is significantly faster to encode than AVIF. This matters in several scenarios:

• Build-time optimization: Processing hundreds of images during a website build is much faster with WebP
• On-the-fly conversion: CDNs and image services can convert to WebP in real-time more easily
• User-generated content: Websites that process user uploads can convert to WebP faster, reducing server load

AVIF encoding can be 5-10× slower than WebP, depending on quality settings. For a single image, this is negligible. For batch processing thousands of images, it becomes a real consideration.

Decoding Speed

WebP decodes faster than AVIF. On desktop hardware, the difference is minimal — both decode quickly enough that users won't notice. On lower-end mobile devices or when decoding many images at once (like in a gallery), AVIF's slower decoding can impact performance.

Browser vendors continue to optimize AVIF decoding, and hardware acceleration is becoming more common. By late 2025, this gap will likely narrow further.

Use Case Recommendations

Choose AVIF When:

• Bandwidth is critical: Mobile-first sites, markets with slow connections, or apps with large image libraries benefit most from AVIF's superior compression
• Image quality is paramount: Photography portfolios, e-commerce product images, and visual-heavy sites get better results with AVIF
• You have build-time optimization: If you're pre-processing images during a build step, encoding time is less of a concern
• Supporting modern browsers: If your analytics show 90%+ of users on current browsers, AVIF is a safe choice

Choose WebP When:

• You need on-the-fly conversion: Real-time image processing, CDN transformations, or user-uploaded content favor WebP's faster encoding
• Maximum compatibility matters: If you need to support older browsers without fallbacks, WebP's broader support is safer
• You're processing lots of images: Large-scale image libraries or frequent batch processing benefits from WebP's speed
• Simple graphics and UI: For non-photographic content, WebP's good-enough compression and fast encoding make it a pragmatic choice

Use Both (Best of Both Worlds):

The most effective strategy in 2025 is to serve both formats using the HTML <picture> element:

<picture>
  <source srcset="image.avif" type="image/avif">
  <source srcset="image.webp" type="image/webp">
  <img src="image.jpg" alt="Description">
</picture>

This approach delivers:

• AVIF to browsers that support it (smallest files, best quality)
• WebP to browsers that support it but not AVIF (good compression, wide support)
• JPEG fallback for older browsers (universal compatibility)

Modern CDNs and image services (Cloudflare Images, Cloudinary, Imgix) handle this automatically, detecting browser support and serving the optimal format.

Implementation Examples

HTML Picture Element

The most straightforward implementation for static sites:

<picture>
  <source
    srcset="hero-400.avif 400w, hero-800.avif 800w, hero-1200.avif 1200w"
    sizes="(max-width: 600px) 400px, (max-width: 1200px) 800px, 1200px"
    type="image/avif">
  <source
    srcset="hero-400.webp 400w, hero-800.webp 800w, hero-1200.webp 1200w"
    sizes="(max-width: 600px) 400px, (max-width: 1200px) 800px, 1200px"
    type="image/webp">
  <img
    src="hero-800.jpg"
    srcset="hero-400.jpg 400w, hero-800.jpg 800w, hero-1200.jpg 1200w"
    sizes="(max-width: 600px) 400px, (max-width: 1200px) 800px, 1200px"
    alt="Hero image"
    loading="lazy">
</picture>

Server-Side Content Negotiation

For dynamic sites, detect the Accept header and serve the appropriate format:

// Node.js/Express example
app.get('/images/:filename', (req, res) => {
  const accept = req.headers.accept || '';
  const filename = req.params.filename;

  if (accept.includes('image/avif')) {
    res.sendFile(`${filename}.avif`);
  } else if (accept.includes('image/webp')) {
    res.sendFile(`${filename}.webp`);
  } else {
    res.sendFile(`${filename}.jpg`);
  }
});

CDN Auto-Format

Most modern CDNs handle this automatically. For example, Cloudflare's automatic image optimization:

<!-- Just use a regular img tag -->
<img src="https://yoursite.com/image.jpg" alt="Description">

<!-- Cloudflare automatically serves WebP or AVIF based on browser support -->

Tools and Encoding

Command-Line Tools

For WebP:

• cwebp (official Google tool): Fast, reliable, widely supported
• imagemagick: Good for batch processing
• sharp (Node.js): Excellent for build pipelines

For AVIF:

• avifenc (libavif): Official encoder, most options
• imagemagick (7.0+): Supports AVIF encoding
• sharp (Node.js): AVIF support via libvips

GUI Tools

• Squoosh: Google's web-based image optimizer supports both formats with visual comparisons
• ImageOptim (Mac): Batch processing for both formats
• GIMP: Supports WebP and AVIF export with quality controls

Build Tools

• next-image: Next.js automatic image optimization supports both formats
• webpack image loaders: Automate conversion during build
• gulp/grunt plugins: Available for both formats

Performance Impact

Real-world performance testing shows significant benefits from modern image formats:

• Page load time: Sites switching from JPEG to WebP see 20-35% faster image loading. Switching to AVIF shows 30-50% improvement.
• Bandwidth savings: For image-heavy sites, switching to AVIF can reduce bandwidth costs by 40-60% compared to JPEG.
• Core Web Vitals: Smaller images improve LCP (Largest Contentful Paint) and overall page speed scores.
• Mobile experience: The impact is most pronounced on mobile, where users on 3G/4G connections see dramatically faster load times.

The Verdict

In 2025, there's no single "winner" — both formats have earned their place in the modern web developer's toolkit.

AVIF is the future. Its superior compression and quality make it the best choice for bandwidth-constrained scenarios and visual-heavy sites. As browser support approaches WebP's levels and tooling matures, AVIF will likely become the new standard.

WebP is the pragmatic choice. Its combination of excellent compression, fast encoding, and near-universal browser support make it a safe, effective option that works for almost every use case today.

The best strategy: Use both. Serve AVIF to browsers that support it, WebP as a middle ground, and JPEG as a fallback. This ensures the best possible experience for all users while maximizing performance gains.

For new projects starting in 2025, implement multi-format support from day one. The performance benefits are too significant to ignore, and the implementation complexity is minimal with modern tools and CDNs.

Related Articles

• Complete Guide to Image File Formats - Deep dive into all web image formats
• Image Optimization Guide - Best practices for fast-loading images
• Image Compressor Tool - Compress images to WebP and other formats
• 5 Common Image Optimization Mistakes - Avoid these pitfalls