JPG to WebP converter
WebP stores the same photograph in noticeably less space than JPG. If the images are going on a website, this is the straightforward win. It runs on your device.
Converting JPGs to WebP
- WebP is already selected above.
- Drop your JPG images in, or click to browse.
- Download the result. It never left your device.
For a folder, select all of it at once rather than dropping files one at a time — the results come back together as a single zip.
The one image optimisation nobody argues about
This is the most common image optimisation on the web, and for once the recommendation is uncontroversial: at a matched quality, WebP is typically 25 to 35 percent smaller than JPG.
Where it pays is a page carrying many photographs. Cutting a third off every image is the difference between a product page that appears immediately on a phone connection and one where the pictures fill in slowly as you scroll.
Unlike the AVIF version of this conversion, there is very little to weigh up. Every browser released in the last several years reads WebP.
What changes in the picture
- The file gets meaningfully smaller with no visible difference at normal viewing size.
- The image is re-encoded at a quality of 90, so this is a second lossy pass over an already lossy file. It is not visible in practice, but converting back and forth repeatedly is still a bad habit.
- WebP can store transparency; a JPG has none, so the result is opaque. That only matters if you were hoping the conversion would add it, which it cannot.
Doing a whole folder, and what it costs your browser
This is the page people arrive at with a folder rather than a file, so here is exactly what happens when you drop fifty photos on it at once.
They are converted one after another, not all at once. That sounds slower and is the reason it finishes at all: a phone asked to decode fifty 12-megapixel pictures simultaneously runs out of memory and the tab dies. Going in sequence means only one decoded picture and the finished files are ever in memory together. Measured on a desktop, 200 twelve-megapixel photos ran to completion in 72 seconds with the JavaScript heap peaking at 38 MB.
The limit is 50 rather than unlimited because that desktop measurement is the only one there is — no phone was ever measured, so the number that would actually matter is unknown, and fifty is about eighteen seconds of work on the machine that was measured. Drop more than fifty and the extras are not silently discarded: they are counted and named so you know what to put in the next batch.
Three smaller things that matter on a batch and not on a single file. One unreadable picture does not stop the run — the rest finish and you are told which one failed. More than one result comes back as a single zip, because browsers block several downloads arriving at the same moment. And every output filename gets a short random tag before its extension, like photo-8f2a1c.webp, so that two files with the same name from different folders never overwrite each other in your downloads.
Questions before you convert a site’s images
How much smaller will my photos get?
Usually a quarter to a third. Photos with large smooth areas, like skies and studio backgrounds, gain more; busy detailed scenes gain less.
Will the photo look worse?
Not at normal viewing size. It is a second lossy encode at quality 90, so zoomed right in on fine detail a difference exists, but it is not what anyone looking at the photo will see.
Can I convert a whole folder at once?
Yes, up to 50 pictures per go, and they come back as a single zip. Anything past 50 is counted and reported rather than dropped, so you know what is left for the next batch.
What happens if one of the files is broken?
The rest still convert. The run does not stop, and the failure is listed by filename at the end so you can see which one to look at.
Nothing is uploaded
It runs on your device. Turn the network off mid-conversion and it still finishes — or check any converter yourself.
Free, and no account
No signup, no watermark, no upgrade prompt. No size cap beyond your own device, and up to 50 pictures a go.
The other target worth considering
- JPG to PNG When something downstream will only take a PNG.
- HEIC to WebP Keeps HEIC-like file sizes, but the web can actually read it.
- PNG to WebP Smaller than PNG, and transparency still survives.
Or open the image converter to pick any combination, and the image compressor when the problem is size rather than format.