Popularity: 4. How many sugar does a kit kat have? A mini bar has 4.9 grams, a 42 gram (1.5 oz.) bar has 20.2 grams of sugar, a 46 gram bar has 22.4 grams, a 78 gram bar has 38 grams of sugar, and a 96 gram bar has 46.7 grams of bad stuff.