Comparison: All Leuchtturm1917 notebook form factors
I am a huge fanboy of the German stationery brand Leuchtturm1917.1 A few months ago, I wondered about the notebook-price-ratio of each of the different formats LT1917 offers — from A6 to A4+.
So I did the math — or rather, the Excel formulas. Here are the results:

(HC = hardcover, SC = softcover)
You're welcome.

Footnotes
If you ever wonderd: "Leuchtturm" is the German word for "lighthouse". And yes, it's hard to pronounce for any non-German speaker.↩