What is the difference between JPG and JPEG?

There is no technical difference. JPEG is the format name; JPG is a shortened 3-letter extension from early Windows. Both extensions refer to identical files using the same JPEG compression standard.

More about converting JPG to JPEG

JPG and JPEG are the same format - There is no technical difference whatsoever. JPEG (Joint Photographic Experts Group) is the formal name of the format. The .jpg extension exists because early Windows operating systems (MS-DOS, Windows 3.x) enforced a 3-character limit on file extensions, so .jpeg was shortened to .jpg. Modern operating systems use both interchangeably.

The only reason to 'convert' from .jpg to .jpeg is to rename the file extension. Some legacy software, shell scripts, or automated workflows may be hardcoded to accept only .jpeg files and reject .jpg. This tool provides a simple way to re-encode your image with the .jpeg extension.

When you'd use this

Reasons to convert JPG to JPEG usually come down to compatibility, file-size, or specific feature requirements. Common situations:

  • An app or platform only accepts JPEG uploads.
  • You need a feature unique to JPEG (e.g. transparency, vector scaling, animation, multi-page pages, etc.) that JPG doesn't provide.
  • You're optimising file size — modern formats often produce smaller files than the older format you started with.
  • You need a single archival format across a project so files behave consistently in the same viewer.

How to do it in jpg.now

  1. Open the JPG → JPEG tool on jpg.now.
  2. Drag your JPG file onto the drop zone, or click Select files. You can drop a whole folder of files at once.
  3. The output is fixed to JPEG. If the format supports extra options (page size, transparency background, quality, EXIF stripping), tweak them in the right-hand panel.
  4. Click Convert. The job runs on our server and finishes in a few seconds for typical photos.
  5. Download the result. Files stay in storage for 24 hours and are then permanently deleted.

The entire flow is free for the first 10 jobs per day with no signup required. A free account doubles that quota; a premium plan removes the limit entirely.

Tips and common pitfalls

  • If all you need is to rename the extension, you can do so directly in Finder (Mac) or Windows Explorer - Right-click → Rename → change .jpg to .jpeg. No re-encoding is needed.
  • If you need to use this tool for a workflow that requires .jpeg extension, set quality to 100% to avoid any additional compression.
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