No. Efficiency is a measurement personal to you and your equipment. Each time you brew an all grain batch you measure the volume of the wort going into the fermenter and the specific gravity of that wort as well. Then use the calculator to see what brew house efficiency you achieved. Use that brew house efficiency value the next time you design a recipe to better predict what your OG will be.
When you get a recipe online or in a book it will have an efficiency assumption. You replace that assumption with your actual efficiency and change grain weights accordingly to hit the target OG with your brew system.
