Clicky: The Vapors Toolbox
This little app will allow you to specify how much wire you'll need for which type of coil you are building and how many of them you'll need by adding some inputs like which wire gauge be using along with the diameter of the coil you'll be building.
A few added features like the power tool for Wattage calculations and a unit converter makes this a nifty little app for the avid tinkerer.
Go get it. Thank me later.