Here are some useful calculators:
Alcohol by volume
Use these calculators to estimate alcohol content.
Alcohol by volume: simplified calculation
Use this simplified calculator to estimate the alcohol level.
Alcohol by volume: alternative calculation for high gravity beers
Higher alcohol levels slightly distort hydrometer readings. Use this alternative calculation for high-gravity beers.
Use this calculator to calculate your beer’s relative bitterness. It compares IBU level with original grabity. Enter your final density for a calculation that takes into account the level of attenuation.
Note : concept and calculations for taking attenuation have been developed by the Mad Alchemist. I merely included it in this calculator.
As an indication, here is an image of bitterness ratios by style. Unfortunately, I can’t trace the source (my apologies to the person who made this graph):