So my very first batch (IPA) is in my 5 gallon glass carboy and it's clearly not 5 gallons. I followed the instructions by steeping the specialty grains in 2.5 gallons of water @ 160 degrees for 30 min., added 7 pounds of LME plus the bittering hops, boiled for 55 min., added my finishing hops and let boil for 5 more mins (my 3 gallon kettle barely held it all in without boiling over). I chilled the wort, transferred it to my 5 gal carboy and then added another 2.5 gal of water and my White Labs liquid British Ale yeast but it's clearly not 5 gallons. I stupidly didn't take the time to measure my carboy so I don't even know where the 5 gallon mark is but the level in my kettle dropped substantially during the hour-long boil and from photos of marked carboys I've found I'm guesstimating I have about 4.5 gallons (including trub).
I guess I'll find out how it turned out when it's ready to drink so my question is this: Do most recipes account for evaporation or should I be adding extra water (say 3 gallons instead of 2.5) for my next brew?