I know there are plenty of rune word calculators out there but I wanted to make one for our diablo fan site and after it turned out pretty decently, I decided to translate it and share it with more people on the internet. You will find it on this address: https://d3bg.org/runewords-calculator/
There are two key features that make it kind of unique and different from other calculators:
It remembers the runes you select so that if you close the window, you won't have to click on every rune next time you open it up.
There is an option to filter rune words by item bases. Let's say you find a normal item with many sockets but are unsure if it's worth keeping. You can easily filter all rune words that require X amount of sockets for a given item and see if you can use it for a rune word.