Well, he is a frost giant...

When I was writing my Molly/Alec fic, I was trying to figure out what their height difference would look like. Turns out, Daniel Radcliffe has my back. Dan is 1-2 inches taller than Loo Brealey, but probably about the same as Molly in her shoes.

There is also a useful height comparison tool, where you can enter the height of yourself (or one character) and choose a celebrity (one that matches the height of your other character) and it will do a rough comparison of height.

Now you know.