Alpha conversion formula

[Fatboy4Life]

I'm brewing today and I reallized that the hops I bought are 14% alpha where the recipe calls for 13% alpha. I'm sure I've seen a formula for adjusting the amount of hops used based on Alpha but not sure where to find it. Does anyone have a simple formula?

 

[BigEd]

It's just simple algebra. For example, if the recipe calls for 2 oz of 8%AA and you have 6%AA hops you divide 6 into 8 which yields 1.33. Then multiply 2 oz by 1.33 to find out the quantity of 6%AA hops needed to equal the 8%AA variety.

 

[Fatboy4Life]

Perfect, thanks Ed.