Why WEBP Images Make Your Website Faster and Help Your SEO

Website speed is not just about user experience — it is a direct Google ranking factor. Since Google made Core Web Vitals a ranking signal in 2021, page loading performance has had a measurable and documented impact on where your website appears in search results. Images are consistently the largest contributor to page weight, often accounting for 50–80% of total page size on content-heavy websites. WEBP is the format that directly addresses this problem. Developed specifically for the modern web by Google's own engineers, WEBP delivers dramatic file size reductions without visible quality loss — making it the single most impactful change you can make to improve your website's speed and search performance.

How Much Smaller Are WEBP Files Compared to PNG?

WEBP files are typically 25–35% smaller than equivalent PNG files when using lossless WEBP compression. When using lossy WEBP at high quality settings (80–90%), the savings are even greater: typically 60–75% smaller than PNG at visually equivalent quality. Google's own research, published as part of the WEBP specification, showed that lossless WEBP images are on average 26% smaller than PNG, and lossy WEBP images are 25–34% smaller than comparable JPEG images. To translate this into practical terms: a hero image that currently weighs 500KB as a PNG would typically come in at around 120–160KB as a WEBP at 85% quality — a saving of over 300KB on a single image. Multiply this across a website with dozens of images and the cumulative performance improvement is enormous.

What Are Google Core Web Vitals and Why Do Images Matter?

Core Web Vitals are a specific set of metrics Google uses to measure real-world user experience on websites. The three primary metrics are Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), and Interaction to Next Paint (INP). For image-heavy pages, LCP is the most critical metric to optimize. LCP measures how long it takes for the largest visible element on the page to fully load and paint to the screen — and for the vast majority of websites, that largest element is an image: a hero banner, a featured product photo, or a blog post image. A large, unoptimized PNG hero image can push LCP to 4 or 5 seconds on average connections. Converting that same image to WEBP at 85% quality can cut the file size by 70%, directly reducing the LCP time and potentially moving your score from Google's "Poor" or "Needs Improvement" category into the "Good" range.

Does Google Recommend WEBP?

Yes — explicitly and repeatedly. Google PageSpeed Insights includes a specific performance audit called "Serve images in next-gen formats" that flags any images served as PNG or JPEG and recommends converting them to WEBP or AVIF. This recommendation directly improves your PageSpeed score, which is a weighted performance metric that influences how Google assesses your page's technical quality. Google's own developers have written extensively about WEBP as the preferred web image format, and Chrome DevTools and Lighthouse both treat WEBP adoption as a best practice. Sites that follow this recommendation consistently see measurable improvements in both PageSpeed scores and real-world Core Web Vitals measurements.

WEBP vs PNG vs JPEG — File Size Comparison

How to Convert Your Website Images to WEBP for Free

Converting your existing website images to WEBP is straightforward using Convertify:

1. Go to Convertify's PNG to WEBP converter
2. Upload your PNG image — drag and drop it onto the converter or click to browse
3. Adjust the quality slider — 85% is the recommended starting point for most web images
4. Click "Convert to WEBP"
5. Preview the result to confirm quality looks good
6. Download your WEBP file and replace the PNG on your website

For websites with many images, use Convertify's batch conversion feature to convert up to 15 PNG files at once and download them all as a single ZIP file. This is particularly useful for developers optimizing an entire site or bloggers updating older posts with better-performing image formats.

Will Switching to WEBP Break Anything?

For virtually all visitors in 2025, no. Browser support for WEBP is now over 97% globally, covering all modern versions of Chrome, Firefox, Safari, Edge, and Opera. If you're concerned about the remaining 2–3% on very outdated browsers — primarily older versions of Internet Explorer that haven't received updates in many years — you can use the HTML <picture> element to serve WEBP to modern browsers while providing a PNG fallback for legacy ones:

This approach gives the speed benefits of WEBP to 97%+ of your visitors while ensuring the remaining few still see a working image. For most websites, however, simply switching all images to WEBP without a fallback is completely safe in 2025 — legacy browser traffic is typically less than 1% of total visitors.

How Much Can WEBP Improve Your PageSpeed Score?

The improvement depends heavily on how image-heavy your site currently is and what format you're serving. Sites that are currently using large PNG files — especially for hero images, product photos, or blog thumbnails — typically see the largest gains. Converting just the hero image and the primary content images on a typical landing page can improve PageSpeed Insights scores by 10–30 points in many cases. More importantly, you'll see real-world LCP improvements that can move your Core Web Vitals from Google's "Needs Improvement" rating to "Good" — a meaningful SEO benefit that affects how your pages rank in competitive searches.