We know that the Universe evolved from a very low entropy state in the early universe to very high entropy state of today's universe.
What is the quantitative definition of the net entropy of the present universe?
How can we measure the net entropy or its change in the universe today?
I want some concept and formulas related to that and I'm not talking about the early universe. The question What is the entropy of the universe today? discusses theoretical calculation of the entropy but not experimental measurements of it. An experimentalist's or observers perspective might also be illuminating for me.