WebP vs AVIF: Which Image Format Should You Choose in 2025?

The Modern Image Format Landscape

Choosing the right image format can reduce your page load time by 50% or more. In this guide, we compare the two leading next-gen formats: WebP and AVIF.

Images account for roughly 40-60% of total page weight across the web. Switching from JPEG to a modern format is often the single highest-impact optimization you can make — and it requires zero changes to your layout or design.

Compression Efficiency

AVIF typically achieves 20-30% smaller file sizes than WebP at equivalent visual quality, thanks to the AV1 codec. However, WebP still outperforms JPEG by 25-35%.

Format

Avg. Savings vs JPEG

Encoding Speed

WebP	25-35%	Fast
AVIF	40-50%	Slower

In real-world testing with a 4000×3000 landscape photo at quality 80:

JPEG: 2.4 MB

WebP: 1.6 MB (33% smaller)

AVIF: 1.1 MB (54% smaller)

The savings compound across a page. A product listing with 20 images could drop from 48 MB (JPEG) to 22 MB (AVIF) — a 54% reduction in total image weight.

Encoding Speed Matters

Not all compression is equal when you need real-time conversion:

WebP encodes in ~50-200ms per image (suitable for on-the-fly CDN transforms)

AVIF encodes in ~500-2000ms per image (better for build-time or batch processing)

If you run a high-traffic e-commerce site that generates thumbnails on the fly, WebP's speed advantage is significant. For static hero images or pre-processed galleries, AVIF's superior compression wins.

Browser Support

WebP: Supported by all modern browsers (97%+ global coverage) — Chrome, Firefox, Safari, Edge, Opera, Samsung Internet

AVIF: Supported by Chrome, Firefox, Safari 16+ (92%+ global coverage) — not yet supported in older Safari versions and some embedded browsers

For the latest compatibility data, see our AVIF Browser Support Guide.

When to Use WebP

You need fast encoding for real-time conversion

Maximum browser compatibility is critical

You're serving e-commerce product images at scale

Your CDN performs on-the-fly image transforms

You need animated images (WebP supports animation, unlike AVIF still images)

When to Use AVIF

You want the smallest possible file sizes

Your audience uses modern browsers

You're optimizing hero images and large photography

You pre-process images at build time

Bandwidth costs are a major concern (mobile users, emerging markets)

The Best Strategy: Serve Both

Use the element to serve AVIF with WebP fallback:

``html `

The browser evaluates each in order and picks the first format it supports. If none match, it falls back to the tag. This guarantees every visitor sees an image — and the most efficient one their browser can handle.

Responsive Images with Size Attributes

Combine format selection with responsive sizing for maximum impact:

`html `

Always include width and height attributes to prevent Cumulative Layout Shift (CLS) — a Core Web Vitals metric that Google uses for ranking.

Common Pitfalls to Avoid

Converting already-compressed images: If your source is a low-quality JPEG, converting to WebP won't recover detail. Start with the highest quality source.

Using quality 100: This produces unnecessarily large files. Quality 80-85 is the sweet spot for most photos.

Ignoring alpha channels: For images with transparency, WebP and AVIF both support alpha, but AVIF's transparency compression is significantly better.

Forgetting the fallback: Without a JPEG/PNG fallback in the ` tag, very old browsers will show a broken image.

Real-World Case Study: E-Commerce Product Page

We tested this approach on a Shopify store with 150 product pages, each containing 8–12 product images (average 1800×1800px, ~350KB JPEG each).

Before optimization:

Average page weight: 5.2 MB (images only)

LCP on 4G: 4.8 seconds

Google PageSpeed score: 42/100

After converting to WebP (quality 82) with resizing to 1200×1200:

Average page weight: 1.4 MB (images only) — 73% reduction

LCP on 4G: 2.1 seconds — 56% faster

Google PageSpeed score: 78/100

After switching hero images to AVIF (quality 78):

Average page weight: 1.1 MB (images only) — 79% reduction from original

LCP on 4G: 1.8 seconds — 62% faster

Google PageSpeed score: 84/100

The key insight: the biggest gains came not just from format conversion, but from resizing images to match their display dimensions. Most product photos were being served at 3–4x their displayed size. Resize first, convert second.

Try It Yourself

Our Bulk Image Converter lets you convert images to both WebP and AVIF directly in your browser — no upload required, completely free. You can also compare quality settings side-by-side to find the optimal balance for your images.

For a complete optimization workflow, check out our guide on How to Compress Images Without Losing Quality.