Calculating aquarium volume: V = L x W x H x 0.00433 (convert cubic inches to gallons) V = L x W x H x 0.0163871 (convert cubic inches to litres) where V is the Volume, L is the Length, W is the Width, H is the Height in inches standard 4 feet tank: 48 x 18 x 14 = 12096 cubic inches 12096 x 0.00433 = 52.37 gallons 12096 x 0.0163871 = 198.22 litres standard 2 x 1 x 1 tank: 24 x 12 x 12 = 3456 cubic inches 3456 x 0.00433 = 14.96 gallons 3456 x 0.0163871 = 56.63 litres