This tiny, free and open source Windows Desktop app lets you save colors to Simple Color Files.
Start by typing a hexadecimal color code (such as #BC1233), or a HTML color name (such as DodgerBlue). You can preview the color, as it fills the bottom half of the interface, in real-time, as you type. You can use the Pick Color link button to open a Color dialog box, and visually select a color. And you can even double-click the color preview rectangle to select a random color.
After typing or selecting a color, click the Save button to open the Save As dialog box. You can customize the location and file name, or simply accept the defaults, and click Save one more time. That's it! Your color has been saved.
You can now open the Simple Color File and view your color using any browser, on any PC, smartphone, or tablet.
"Seamlessly save and share colors and their corresponding codes in multiple devices and browsers using this simple and straightforward tool. ... It comes with a simplistic, yet fresh, stylish and modern interface that is unlikely to give you any troubles." (Softpedia Review)
Simple Color File is available in both installable and portable editions.