Brown sugar in grams, packed and loose

Packed into the cup, brown sugar weighs 213 grams. Spooned in loose it weighs 145, almost a third less from the same cup. No other pantry sugar swings this far on how you fill the measure, which is why every figure here assumes the packed cup a recipe means.

Packed is the only weight worth printing

Brown sugar clumps, so a cupful pressed down holds far more than one shaken in loose. Recipes know this and write to the packed cup without saying so. The two US authorities both measure that packed cup and land close: King Arthur reads 213 g and the USDA 220, 7 grams apart. We follow King Arthur at 213 g, since American recipes are written against it. The reasoning behind picking one authority over another sits on the methodology page.

Packed is the only weight worth printing
AuthorityA packed US cup
King Arthur Baking ingredient weight chart213 g
USDA FoodData Central220 g

Brown sugar conversions in full

Brown sugar conversions in full
Brown sugar (packed)GramsOunces
1/4 cup53.3 g1.9 oz
1/3 cup71 g2.5 oz
1/2 cup107 g3.8 oz
2/3 cup142 g5 oz
3/4 cup160 g5.6 oz
1 cup213 g7.5 oz
2 cups426 g15 oz

Density used: 0.90 g per ml, for the packed cup.

Packed against loose: a third of the sugar

How firmly you fill the cup moves the weight further than any argument between charts. The USDA measured both ends of the same cup:

Packed against loose: a third of the sugar
How you fill itA US cup
packed213 g
unpacked145 g

That is a 68 gram gap on one cup, against the 7 grams the two authorities argue over when both pack it. Press the sugar in with the back of a spoon until it mounds and keeps the cup's shape when you turn it out, and you land on the 213 g this page publishes. Spoon it in loose and you are 68 g short before the recipe starts.

Brown sugar in a metric cup, and the cup we leave blank

A firmly packed metric cup of brown sugar is 200 g, and this is one place Australia and New Zealand agree: Edmonds, Chelsea and Sanitarium all print 200, while only Australian Women's Weekly reads 220. On flour those same countries part ways by 25 grams, so their agreement on brown sugar is the exception. We leave the Japanese cup blank on purpose. The Japanese tables do carry a brown sugar, but it is a dry granular one and a separate sanontou, neither the moist packed sugar an American recipe means, so a figure here would be a confident wrong answer rather than a missing one.

Questions about brown sugar weight

How many grams is a cup of brown sugar?
213 g packed, the King Arthur figure this page uses. Packed means pressed into the cup so it holds its shape when tipped out, and it is the only way brown sugar is measured.
What if a recipe does not say packed?
Assume packed. Almost every recipe means it, because loose brown sugar is unreliable to measure. A loose cup is only 145 g by the USDA, 68 g short of a packed one, enough to throw off a small batch.
How much is a teaspoon of brown sugar?
4.6 g packed, from the USDA. Brown sugar holds together on a spoon the way it does in a cup, so a teaspoon presses down the same way a cup does.

Sources

King Arthur Baking for the 213 gram packed cup and the USDA FoodData Central SR Legacy for the 220 gram packed cup, the 145 gram loose cup and the 4.6 gram teaspoon. Edmonds, Chelsea, Sanitarium and Australian Women's Weekly for the metric cup. Full citations on the sources page.