You can calculate it by yourself or let software do it for you.
Mash volume: 1.25-1.50 qt/lb
Sparge volume: Pre-boil volume - 1st running volume
Fermentation volume: Post-boil volume - boil kettle dead space and siphoning losses (-4% due to temperature shrinkage)
Is 5.5 gallons pre-ferment about right for a five gallon batch? Most recipes it seems doesnt tell you how much water to use. I thought I had enough last time. I only have a little more than 6 gallons left in a double batch of pliny the elder. I cant just heat a bunch of water up. Our water is terrible. I buy a gallon at a time.