Images are usually the heaviest thing on a web page. On a typical website they account for well over half of the total download size, which means the format you choose for your pictures has an outsized effect on how quickly your pages appear. WebP is the format designed to fix exactly that problem: smaller files, the same visual quality, and modern features such as transparency and animation, all in one place. If you have been asking yourself why WebP keeps coming up in performance and SEO advice, this guide gives you the complete answer.
What is WebP?
WebP (pronounced "weppy", with the file extension .webp) is an image format created by Google and first released in 2010. It was built specifically for the web, with a single goal in mind: to make high-quality images that download faster than the older formats we have all relied on for decades. It began life using the same compression technology as the VP8 video codec, and it has been refined steadily ever since.
Unlike JPEG, which only does lossy compression, and PNG, which only does lossless, WebP is unusual in offering both approaches in a single format. It also supports full alpha transparency and short animations, features that previously forced you to juggle several different file types. In short, WebP is a modern, all-purpose image format that aims to replace JPEG, PNG and animated GIF for everyday use on websites.
How WebP works
WebP's advantage comes from smarter, more modern compression than the formats it replaces. It is worth understanding the two modes, because knowing the difference helps you pick the right one for each image.
- Lossy WebP works like a more advanced version of JPEG. It uses block prediction and better entropy coding to remove detail the human eye is unlikely to notice, producing dramatically smaller files. This mode is ideal for photographs and rich, colourful images.
- Lossless WebP works like a more efficient PNG. It reconstructs every pixel exactly, with no quality loss at all, while still compressing more tightly than PNG does. This mode is ideal for logos, icons, illustrations, screenshots and anything with sharp edges or text.
On top of those two modes, WebP adds transparency (an alpha channel) in both lossy and lossless files, something JPEG cannot do at all. It also supports animation, making it a far lighter, smoother replacement for the ageing animated GIF. If you would like to understand the trade-off between the two modes in more depth, our guide to lossless vs lossy compression explains it in plain English.
Why WebP is important
The reason WebP matters is simple: speed is no longer optional on the web. Visitors expect pages to appear almost instantly, and they abandon sites that make them wait. Search engines have taken notice too, and now use real-world loading performance as a ranking signal. Because images are the biggest single contributor to page weight, shrinking them is the fastest route to a quicker site, and WebP shrinks them better than almost anything else you can serve today.
There is also a growing cost and sustainability angle. Every megabyte you send is bandwidth someone has to pay for and energy that has to be spent. Multiply a heavy page by thousands of visitors a month and the savings from a smaller format become very real, both for your hosting bill and for the mobile-data allowances of the people visiting you. WebP lets you serve the same experience using far fewer bytes.
The benefits of using WebP on your website
Here is the practical payoff, and why so many UK site owners are moving their images across to WebP.
- Significantly smaller files. WebP typically produces the smallest files of any widely supported web format, for both photographs and graphics. Smaller files are the foundation of every other benefit below.
- Faster page loads. Lighter images download and render sooner, which improves your Largest Contentful Paint and makes the whole page feel snappier, especially on mobile connections.
- Better SEO. Google uses page speed and Core Web Vitals as ranking factors, so faster, lighter pages can improve your visibility in search results.
- Lower bounce rates and higher conversions. Visitors are far more likely to stay, read and buy when a page loads quickly. Speed is quietly one of the most effective conversion improvements you can make.
- Reduced bandwidth and hosting costs. Serving fewer bytes to every visitor lowers your data transfer, which can meaningfully cut costs on busy sites.
- One format for many jobs. Because WebP handles photos, transparent graphics and animation, you can standardise on a single modern format instead of maintaining a mix of JPEG, PNG and GIF.
- Transparency without the weight. You get PNG-style transparency at a fraction of the file size, which is perfect for logos and product images on coloured backgrounds.
- A better mobile experience. Mobile visitors, often on slower or metered connections, benefit most from lighter images, and they now make up the majority of web traffic.
How much smaller are WebP files?
Exact savings depend on the image, but the typical ranges are well established. The table below shows what you can usually expect when converting from an older format to a well-tuned WebP.
| Converting from | WebP mode | Typical size saving | Quality |
|---|---|---|---|
| JPEG (photos) | Lossy | 25 to 35% smaller | Visually identical |
| PNG (graphics, logos) | Lossless | 20 to 30% smaller | Pixel-perfect |
| PNG (photos) | Lossy | Often 60 to 80% smaller | Visually identical |
| Animated GIF | Lossy or lossless | Frequently 60%+ smaller | Smoother, more colours |
The easiest way to see the numbers for your own images is to try them. Our free tool produces both a lossless and a lossy WebP for every file and shows the exact size of each, so you can choose the smaller option with total confidence. For a direct head-to-head, see our WebP vs JPG vs PNG comparison.
WebP, SEO and Core Web Vitals
It is worth spelling out the search-engine benefit, because it is the reason many people first hear about WebP. Google measures the real loading experience of your pages through Core Web Vitals, a set of metrics that includes Largest Contentful Paint (how quickly the main content appears). Large images are one of the most common reasons that metric is poor. By switching your images to WebP and compressing them sensibly, you reduce the number of bytes the browser must fetch before it can paint the page, which directly improves that score.
Better Core Web Vitals do not just help rankings. They lift the experience for every visitor, reduce the number of people who give up before the page loads, and make your advertising and marketing spend work harder because more of the traffic you pay for actually arrives. It is one of the rare optimisations that helps users and search engines at the same time.
Browser support for WebP in 2026
A common worry is compatibility, but that concern is now firmly in the past. Every current major browser supports WebP, including Google Chrome, Microsoft Edge, Mozilla Firefox and Apple Safari, on both desktop and mobile. Global support sits comfortably above 97%, so the overwhelming majority of your visitors will see WebP images natively with no special handling required.
For the tiny fraction of very old browsers that cannot display WebP, you can provide a fallback using the HTML <picture> element, which serves a JPEG or PNG to anything that does not understand WebP. This means you can adopt WebP today without leaving anyone behind.
How to start using WebP
Adopting WebP is refreshingly straightforward, and you do not need to be a developer to begin.
- Convert your existing images. Use our free convert to WebP tool to turn JPG, PNG, GIF and other formats into optimised WebP files. Everything happens in your browser, so your images are never uploaded.
- Choose the right mode. Use lossy WebP for photographs and lossless WebP for logos, icons and screenshots. The tool shows both versions with their file sizes so the choice is easy.
- Add a fallback if you need one. For maximum safety on very old browsers, wrap your image in a
<picture>element with a JPEG or PNG source alongside the WebP. - Keep compressing. Converting to WebP is the biggest win, but sensible compression on top squeezes out even more. Our guide on how to compress images walks you through it step by step.
Are there any downsides to WebP?
To be balanced, WebP is not the answer to absolutely everything. If you need a file that opens in every conceivable piece of software, including old email clients and legacy desktop tools, JPEG and PNG still have the edge on universal compatibility. If you are keeping archival master copies for print or future editing, a lossless original in PNG or TIFF remains a sensible choice. And for logos that must scale to any size without blurring, a vector SVG is better than any pixel-based format, WebP included.
For the day-to-day job of displaying images on a website quickly and beautifully, though, WebP is very hard to beat. Those niches aside, it is the format that should be your default for the web.
The bottom line
So, why WebP? Because it delivers the same images your visitors already enjoy using far fewer bytes, which makes your website faster, cheaper to run and better placed to rank. It handles photos, transparent graphics and animation in one modern format, it is supported almost everywhere, and it takes only minutes to adopt. For anyone who cares about performance, user experience or search visibility, moving to WebP is one of the highest-value, lowest-effort improvements available.