Is there an easy way to calculate the bittering unit when dumping your hops into your wort? I have tried to find some easy calculation, but it doesn't seem to make a whole lot of sense. I have been using hop pellets.

For example: I recently brewed a an IPA from a kit which called for 1 oz Pilgrim Hop Pellets, 11 alpha (full boil) and 1 oz First Gold Hop Pellets 7.3 alpha, during the final minute. I added an additional 2 oz of Cascade Hop pellets at approximately 1/4 oz every 7 minutes.

Based on that can someone attempt to tell me the bittering units and how they came up with that calculation? I started brewing about 10 years ago, but took an 8 year hiatus and this was my second batch since returning.

Many Thanks!