What Is WebP? A Technical Overview

WebP is a modern image format developed by Google, first released in 2010 and refined continuously since. It is built on the VP8 video codec and uses advanced prediction encoding to achieve dramatically smaller file sizes than the JPEG and PNG formats that have dominated the web for decades.

Unlike its predecessors, WebP supports both lossy and lossless compression modes, as well as transparency (alpha channel) and even animation — making it a single format that can replace JPG, PNG, and even GIF in most web contexts.

WebP vs JPG vs PNG — Full Comparison

Here is how the three formats compare across every dimension that matters for web developers and SEO professionals:

Browser Support: Is WebP Safe to Use?

WebP is supported by all major browsers released since 2020. This includes Chrome (since v32), Firefox (since v65), Safari (since v14 — macOS Big Sur and iOS 14), Edge, Opera, Samsung Internet, and all modern mobile browsers. According to caniuse.com, WebP coverage is currently above 97% globally.

For the 3% of users on very old software (primarily Internet Explorer 11 and pre-2020 Safari), you can provide a graceful JPG fallback using the HTML <picture> element, shown below.

How to Implement WebP in HTML (with JPG Fallback)

The <picture> element lets you serve WebP to modern browsers while automatically falling back to JPG for older ones. Browsers that don't support WebP will simply ignore the <source> tag and render the fallback <img>:

<!-- Serve WebP to modern browsers, JPG to older ones -->
<picture>
  <source
    srcset="hero-image.webp"
    type="image/webp"
  />
  <img
    src="hero-image.jpg"
    alt="Hero image description"
    width="1200"
    height="630"
    loading="lazy"
  />
</picture>

For responsive images at different sizes, combine srcset with WebP sources for maximum performance:

<!-- Responsive WebP: serves correct size per screen width -->
<picture>
  <source
    type="image/webp"
    srcset="image-400.webp 400w,
            image-800.webp 800w,
            image-1200.webp 1200w"
    sizes="(max-width: 600px) 100vw, 50vw"
  />
  <img
    src="image-800.jpg"
    alt="Descriptive alt text"
    loading="lazy"
    decoding="async"
  />
</picture>

How to Convert Images to WebP — The Easiest Method

The fastest and simplest way to convert your JPG or PNG images to WebP is using the free ClearAI Tools image converter. It runs entirely in your browser — no server uploads, no account, no software to install:

• Drag and drop any JPG, PNG, GIF, or BMP files onto the converter.
• Select WebP as the output format.
• Adjust the quality slider (75–85% is the recommended sweet spot).
• Click Convert & Download. Single files download instantly; multiple files download as a ZIP archive.

For large batches of images, see our Batch Convert Guide for a step-by-step workflow. For more on quality settings and compression trade-offs, see the Image Compression Guide.

Impact on SEO and Core Web Vitals

Switching from JPG or PNG to WebP has a direct, measurable impact on your website's SEO performance through Core Web Vitals — Google's set of user experience metrics that have been a ranking factor since 2021:

• LCP (Largest Contentful Paint) — Usually the hero image. A 30% smaller file loads proportionally faster, directly improving LCP, which should be under 2.5 seconds.
• FCP (First Contentful Paint) — Smaller images mean the browser can parse and render visible content faster, improving this early metric.
• Total Blocking Time (TBT) — WebP's efficient decoding puts less strain on the main thread, indirectly improving interactivity scores.

Learn how to interpret these metrics and set improvement targets in the Core Web Vitals guide.