The image below is my first brew (Fat Tire clone). After two weeks in the primary (ale pail) I siphoned to my 5 gallon Better Bottle for a week in secondary before bottling. My concern is that the carboy doesn't look very full to me.
When I topped off my wort in the ale pail on brew day I got it up to the 5 gallon line on the outside of the pail. When I racked to secondary there was some trub that I didn't siphon over, but it didn't seem like that much.
I know it's important to have an estimate as to how much beer I have so I don't over-prime it. And it's kind of bumming me out that I might not get as many bottles as I thought.
Edit Jan 14
I bottled this brew yesterday and got 45 bottles out of it. 45*12oz = 540 oz = 4.2 gallons.