The next question was whether the font included any elements we didn't need. Using the character map viewer provided by Font Drop, we were able to see that our Inter UI font file contained 2,192 characters supporting thirty-nine languages, most of which our website simply didn't need (http://bkaprt.com/swd/04-08/). We used the font subsetting tool from Everything Fonts to strip out the unused characters, leaving us with a subsetted version of Inter UI containing only ninety-eight characters (http://bkaprt.com/swd/04-09/). The final file was a mere 7 KB, a reduction of 97.7 percent in file size compared to the official Inter UI file we'd started with, and without any negative side effects for users of our website. So long as you have control of the font files, and the foundry's license terms allow for web use and optimization, you can repeat this process for almost any font, improving performance and sustainability with just a few minutes of effort.

— Sustainable Web Design by Tom Greenwood (Page 60)