An American relative has asked for an 8.5x4.5in bread pan for Christmas, but UK pan sizes are by weight: 1lb loaf, 2lb loaf, etc.
How much dough would you put into an 8x4 (or 8.5x4.5) pan?
Unfortunately sorting bread pans by loaf weight is very vague. A 1lb light and fluffy white sandwich bread might have about the same size as a 2lb heavy, dense wholegrain or rye bread. Also, do you expect your bread to rise really high over the rim or should that be more of a limit? In short, the size of "a 1lb bread" depends a lot on the kind of bread you have in mind.
A quick Internet check of pan dimensions from various manufactureres confirms that there is no standard size, it seems they vary by up to 50% in volume.
So if your relative's wish list states a pan of a certain size, I suggets you go shopping equipped with a meassuring tape instead of looking for a certain "pound value".
Side note: Most 2lb pans are a tad bigger that the requested size and 1lb ones a bit smaller, but I found one sold in the UK by Williams Sonoma (what a coincidence!) that seems to have exactly the sought-for dimensions.
11 x 7 x 2 inches 6 cups
13 x 9 x 2 inches 14 cups
28 x 18 x 5 cm 1.4 liters
33 x 23 x 5 cm 3.3 liters
8 x 4 x 2 1/2 in. 4 cups
8 1/2x4 1/2x2 1/2 6 cups
9 x 5 x 3 inches 8 cups
20 x 10 x 6 cm 948 ml
21 x 11 x 6 cm 1.4 liters
23 x 13 x 8 cm 1.9 liters
That is the best I can do...
3 1/2 cups of flour is approximately one pound.
Further research and some measuring ...
A 1lb Loaf Pan will have a volume of around 1 litre (or 4 Cups).
You can assume that a Cup is around 240ml, hence the 4 cups to the litre I mentioned above.