When moving it yesterday I sat it next to my 5 gallon beverage dispenser. Odd thing was they were very close in physical size so I measured it & then proceeded to rum an on-line volume calculator. 21" tall.. it tapers from 13" at top to 12" at bottom so I took average of 12.5" from middle. Calculator says 11.156 US gallons if filled to the brim. When filled within 4" from top to allow for foam or cap.. it only holds 9.03 US gallons. I'm disappointed as I hoped I could fit 10 gallon batches into it.Other guy was correct.. lid which must be purchased separately is a loose fit. Likely would allow critters such as gnats or possibly fruit fly's into your must. As I plan to use a grain bag, I am hopeful it will help keep the critters at bay & not turn it all into vinegar.