I prefer this one:
DIY E-Liquid Calculator Ten Flavors With Nicotine Plus PG/VG Adjusting
1) it's online, so it doesn't matter what kind of PC or phone or tablet you use;
2) it's online, so as long as you have an internet connection, your recipes are available... even if your PC crashes, your house burns down, a tornado blows your ass away, your dog eats your recipe notebook, or your ex steals it... etc...
3) up to 10 ingredients, or even 11 if you use the spot where one might add water;
4) you can specify a nic level and PG/VG ratio
for every single ingredient -- a godsend if you use WTA! Or if you're very picky about what PG/VG ratio you end up at, and have a mix of PG and VG based flavors.
Andria