Gram to Cup

80 grams of brown sugar, packed to cups

80 g of brown sugar, packed is about 0.36 cups, which is roughly 3/8 cup or 5.82 tablespoons. That comes from 220 g per US cup. Firmly packed. Loose brown sugar drops to about 200 g a cup.

Measure80 g of brown sugar, packed
Cups0.36
Kitchen measure3/8 cup
Tablespoons5.82
Grams per cup used220 g

Brown sugar is the only common ingredient that recipes tell you to compress on purpose. The molasses coating makes it clump and trap air, so an unpacked cup can weigh 20 g less than a packed one. When a recipe says one cup of brown sugar, it almost always means firmly packed.

Result
0.83 cups
About 7/8 cup of all-purpose flour. 100 g is 3.53 oz by weight.
Assumes spoon-and-level. Scooped flour runs closer to 140 g a cup.

Questions

How many cups is 80 g of brown sugar, packed?
0.36 cups, or about 3/8 cup. That is worked out at 220 g per US cup, and a cup of brown sugar, packed can run 200 to 220 g depending on packing pressure.
How many tablespoons is 80 g of brown sugar, packed?
About 5.82 tablespoons, since one US cup is 16 tablespoons. For small amounts tablespoons are usually the more accurate measure to work with.
Why does 80 g give a different number of cups for other ingredients?
Because cups measure volume and grams measure weight. 80 g of brown sugar, packed is 0.36 cups at 220 g per cup, while the same 80 g of a denser or lighter ingredient fills a different amount of space.

Other amounts of brown sugar, packed

50 g60 g70 g74 g75 g85 g90 g100 g110 g112 g

See all brown sugar, packed conversions or 80 g of every other ingredient.