What is the alcohol content in high gravity?

High gravity generally refers to a high starting sugar content or dissolved solids in a beer prior to fermentation. The more sugars, the higher the specific gravity reading on a hydrometer, thus "high gravity". To know the alcohol content of a specific beer requires knowing the original gravity (OG) prior to fermentation and the final gravity (FG) after fermentation is complete. A high gravity beer could have a high alcohol content but you need to know starting and final gravity to actually determine alcohol content.