Is there a simple formula for determining alcohol content without consulting a table?

All you need to determine alcohol content is the original or starting gravity and the final gravity. Subtract your final gravity from your starting gravity, and multiply the result by 131. For example your OG (original gravity) is 1.060 and your FG (final gravity) is 1.012, 1.060 - 1.012= 0.048. 0.048 x 131= 6.3% alcohol by volume.