Mathematical question

My wife does her online shopping using a similar formula. Things she buys are either tiny, huge or in large quantities. It doesn't help that she has never gone metric.

 

I'm developing an unhealthy interest... just two more minutes and I'm off for some family time. Honest!

OK, let's take a piece of cardboard and cut it into a 1m x 1m square. Repeat, until you have six squares and sore hands. Find some sellotape, construct the shape below and declare it is for celebrating Finnish glory in the winter Olympics, for the school Easter play, for returning unwanted goods or some other noble cause.



Now, Boys and Girls, we are ready to build our box! Here's one I made earlier:



And now for the meaningful stuff.

"Peter" (not his real name), wants to reduce his carbon footprint and orders unwrapped goods from the Famous Grouse distillery by providing his own vessel. He asks the box to be filled to the brim.

How many litres of The Famous Grouse Scotch Whisky will "Peter" get?

 

@Selleri I think you have had too much already.

 

None, as DPD will probably lose the parcel.

 

1000 L in other words enough to cause cirrhosis of the liver.
Two problems: 1) wine in a box yes! whisky in a box no! it comes in barrels.
2) I'm not a fan of Famous Grouse I prefer single malts.