File extensions, URLs, and websites

File extensions

When referring generally to a file extension type, use all uppercase without a period. Add a lowercase s to make plural.

  • GIF
  • PDF
  • JPG
  • HTML

When referring to a specific file, the filename should be lowercase:

  • nyancat.gif
  • howtocat.pdf
  • meandmycat.jpg
  • ilovecats.html

URLs and websites

Capitalize the names of websites and web publications. Don’t italicize. Avoid spelling out URLs, but when you need to, leave off the http://www.

Still need help? Contact Us Contact Us