JPEG and JPG are the same format
There is no technical difference between a .jpeg file and a .jpg file. Both names refer to the same image format, created by the Joint Photographic Experts Group. The three-letter version became common because older versions of Windows only allowed three characters after the dot, while Macs, cameras and many websites kept using the four-letter spelling. Today both extensions coexist, and a photo can arrive with either one depending on the phone, camera or program that saved it.
Because the content is identical, a real conversion isn't needed. What you need is a file whose name ends in .jpg, and that's what this page gives you.
Why some sites still reject .jpeg
In theory, any site that accepts JPG should accept JPEG too. In practice, plenty of upload forms check the file name instead of the content. A job portal, a school platform, a government application or an online shop might list “.jpg” as the only allowed type and refuse a photo that ends in .jpeg, even though it's the same thing. Some older desktop programs and photo frames behave the same way.
Renaming the file by hand works on a computer if you can see extensions, but on a phone it's often hidden or not allowed. Here you select the files, process them and download copies that end in .jpg, ready to upload.
No recompression, no quality loss
Many converters open the JPEG, decode it and save it again as a new JPG. Every time a JPG is saved again it loses a little detail, so that approach makes your photo slightly worse for no reason. ConvertirDocs offers to copy the file without recompressing it: the bytes of the image stay exactly the same and only the extension changes.
Since the file is copied as it is, the photo data inside it is kept too, such as the date the picture was taken and the camera details. If you'd rather strip that information, convert with recompression instead, or send the result to another image tool, which removes EXIF data when it reprocesses the picture.
Private and free
Everything happens in your browser. Your photos are never uploaded to a server or stored anywhere, which matters when the picture is an ID, a passport page or a family photo. There's no account, no email and no limit on the number of files: ConvertirDocs is 100% free.
You can select a whole batch of .jpeg files at once. When there's more than one result, the .jpg files download together in a ZIP, so you don't have to save them one at a time.