The order from least sweet added to most sweet is typically Brut, Extra Dry, Dry, Extra Sec, Sec, Demi-Sec and Doux. Think of "Brut" as being short for “brutally” dry to help you remember the order. Brut—the driest of categories—even further, into "Extra Brut" and "Brut Natural." With Natural being the driest of the dry, indicating that no sugar at all has been added. Yep, the whole reason something liquid can be considered “dry” has to do with the amount of sugar added.
Personally, I don’t care for a very sweet champagne so I always look for the proof. It’s because the yeast that raise the proof do so by ingesting the sugar. Therefore a 13% proof champagne is less sweet than a 11.5%.
(Of course a nod to the seriously wine connoisseurs: Yes, champagne is technically the name that only applies to a sparkling wine made in Champagne region of France. Not unlike all the hot sauces that tried to call themselves Tabasco... Unless you made it in Avery Island, Louisiana that is a no-no!)
DRINK RESPONSIBLY, designate a drive, call a cab, uber or lyft.