Less than 5 gallons...newbie question

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?

Everybody has different evaporation rates. So, if you find out that you need more water, then add more. When your carboy is empty, I'd highly recommend marking it so that you have a better idea what you've got with future brews.

The bright side is that your og will probably be a little higher so even though you'll have less beer, you'll have more abv =P

i wouldnt worry abolut it too much. You will have a great beer whether its 4.5 gals, 5 gals, or 5.5 gals. you will likely have a bit stronger beer maybe more malty at 4.5 - at 5.5 you would likely have a thinner less bodied beer with slightly lower alcohol maybe a bit dryer.

Thats all the fun wiht this hobby, it really not a mistake, just a different variation on the beer. Let us all know how it comes out in a couple of weeks!

It's easy to not notice little things like that until you find yourself scratching your head and wondering what to do next. Let us know how your batch turns out. I'm sure it will be fine. Make sure you document little things like that in a journal so you remember to avoid the same mistakes in the future.

Happy Brewing!
D