Grams of Powdered Sugar to Cups
Convert grams of unsifted powdered sugar to cups at 113 g a cup — sifting changes the answer, not the weight.
Updated
cups of powdered sugar (unsifted)
0.88cups
100 grams of powdered sugar (unsifted) = 0.88 cups
Values use the 240 ml US cup, spoon-and-level — your bag’s label may differ slightly.
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In short
How many cups is 100 grams of powdered sugar?
0.88 cups, just under a full cup. One unsifted cup of powdered sugar weighs 113 g. Sifting does not change the weight at all, but it makes the sugar fluffier, so the same 100 g then fills noticeably more than 0.88 cups.
Sifting moves the cups and never the grams. That asymmetry is the whole reason to work from weight.
Grams to cups — quick reference
| Powdered sugar (unsifted) (g) | Cups |
|---|---|
| 25 g | 0.22 cups |
| 50 g | 0.44 cups |
| 75 g | 0.66 cups |
| 100 g | 0.88 cups |
| 125 g | 1.11 cups |
| 150 g | 1.33 cups |
| 200 g | 1.77 cups |
| 250 g | 2.21 cups |
| 500 g | 4.42 cups |
The formula, worked line by line
One division by 113. What makes this ingredient interesting is not the division but the fact that one of its variables moves the answer while leaving the input untouched, which is unusual enough to be worth naming.
“Sifting changes the cups and never the grams. That is the whole argument for working from weight rather than volume.”
A recipe written in grams cannot be affected by whether you sift, because the sugar weighs what it weighs. A recipe written in cups is a recipe with an unstated sifting assumption embedded in it.
cups = grams / 113
grams = cups x 113
100 g / 113 = 0.88 cups
500 g / 113 = 4.42 cups
granulated for comparison: 100 g / 200 = 0.5 cups- Recipe asks for
- 1 cup granulated sugar
- That weighs
- 200 g
- One cup of powdered instead
- 113 g
- Sugar missing
- 87 g
- As a proportion
- about 44 percent
- Verdict
- not a substitution, a different recipe
Nearly half the sugar absent, plus a few grams of cornstarch introduced that the recipe never accounted for. In a creamed cake the missing crystals also mean no aeration, because it is the sharp edges of granulated sugar cutting into butter that create the air in the first place.
Why powdered sugar cannot cream butter
Creaming works because hard sugar crystals tear small pockets into the fat as they are beaten through it. Powdered sugar has no crystals of any size left, so it dissolves into the butter instead of cutting it. The mixture goes smooth and pale but holds far less air, and the bake rises less.
The three sugars, by weight
- Powdered sugar, unsifted
- 113 g
- Granulated white sugar
- 200 g
- Brown sugar, packed
- 213 g
- Powdered sugar, sifted first
- roughly 95 g
Powdered sugar is the lightest thing in the sugar cupboard by a wide margin, and the gap between its sifted and unsifted rows is larger than the gap between granulated and brown. Air is doing more work in this ingredient than the sugar type does in the others.
The practical summary: convert from grams whenever the recipe gives them, sift for texture rather than for measurement, and never trade this sugar against granulated by the cupful.
How to use the grams of powdered sugar to cups
Divide by 113. That is one cup of powdered sugar straight from the box, unsifted and levelled. It is barely more than half the weight of a cup of granulated sugar, which is the first thing to know about this ingredient and the source of most substitution disasters.
The reason is that powdered sugar is granulated sugar ground to a powder, and a powder holds a great deal of air. It is also not pure sugar: most commercial powdered sugar contains a few percent cornstarch to stop it caking, which lightens the cup further and gives it thickening properties granulated sugar does not have.
113 g
One unsifted cup
straight from the box
0.88
Cups in 100 g
just under one
56%
Of the weight of a cup of granulated
113 against 200
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Sifting is where this page differs from every other ingredient on the shelf. Sifting does not remove or add any sugar, so the gram figure is untouched. What it does is break up the clumps and trap more air, so the same sugar occupies more space. Convert from grams and the sifting question never arises; convert from cups and it decides everything.
For most frostings this matters less than the recipes suggest, because you adjust to consistency anyway: too stiff and you add liquid, too loose and you add sugar. Where it matters is anything set by ratio rather than by feel, such as a royal icing that has to flood and then hold an edge.
- 50 g
- 0.44 cups
- 100 g
- 0.88 cups
- 113 g
- 1 cup exactly
- 150 g
- 1.33 cups
- 250 g
- 2.21 cups
- 500 g
- 4.42 cups
A 500 g box is nearly four and a half cups, which is why frosting recipes written in cups run to such large-sounding numbers. Four cups of powdered sugar sounds enormous and weighs 452 g, which is less than a bag of granulated sugar most people would call small.
The sugar this one is most often confused with
Granulated sugar weighs 200 g per cup, nearly twice as much in the same space, which is why swapping the two by volume puts barely half the sugar into the bowl.
Open grams of sugar to cups →Gram weights of powdered sugar converted to unsifted cups at 113 g per cup, with an approximate sifted figure to show which direction the difference runs.
| Grams | Cups (unsifted, 113 g) | Cups (sifted first, about 95 g) |
|---|---|---|
| 25 g | 0.22 | 0.26 |
| 50 g | 0.44 | 0.53 |
| 75 g | 0.66 | 0.79 |
| 100 g | 0.88 | 1.05 |
| 125 g | 1.11 | 1.32 |
| 150 g | 1.33 | 1.58 |
| 200 g | 1.77 | 2.11 |
| 250 g | 2.21 | 2.63 |
| 500 g | 4.42 | 5.26 |
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The cornstarch nobody mentions
Commercial powdered sugar is not only sugar. Manufacturers add a small proportion of cornstarch, typically around three percent, to keep it free-flowing in the box. That addition is invisible in the ingredient list of a recipe and it changes what the sugar does once it is wet.
- Cornstarch content
- about 3 percent, typically
- Purpose in the box
- stops the powder caking
- Effect in frosting
- thickens as it hydrates
- Effect on clarity
- a slight cloudiness in glazes
- Effect if heated in syrup
- can thicken unpredictably
- Practical rule
- good for frosting, poor for syrup
This is why powdered sugar is not a substitute for granulated in anything cooked to a temperature. A caramel or a sugar syrup made with it behaves differently and can seize, and the culprit is an ingredient the recipe never named.
It also explains why frostings thicken as they stand. The starch continues to take up moisture for a while after mixing, so a frosting that looked right in the bowl can be stiff twenty minutes later, and the fix is a splash of liquid rather than more beating.
Measuring a powder that behaves like flour
Everything true about measuring flour is true here, because powdered sugar is a fine powder with the same tendency to trap air and the same tendency to compact under a scooping cup. It also clumps more than flour does, because sugar is hygroscopic and pulls moisture from the air.
Do
- Spoon the sugar into the cup and level with a straight edge
- Sift before measuring only when the recipe says sifted first
- Weigh instead whenever a scale is available
- Add liquid rather than beating longer if a frosting stiffens
Don't
- Scoop the measuring cup through the box
- Substitute powdered for granulated sugar by volume
- Use powdered sugar in a syrup cooked to temperature
- Assume a sifted cup and an unsifted one weigh the same
Clumping is the practical reason to sift even when the recipe does not ask for it. A lump of powdered sugar will not dissolve in a frosting; it stays as a hard speck that shows up on the finished surface. Sifting is a texture step there, not a measuring one, and it can happen after the weighing.
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Questions people ask
How many cups is 100 grams of powdered sugar?
0.88 cups, using 113 g for one unsifted cup measured straight from the box. If the sugar is sifted before measuring it becomes fluffier and the same 100 g fills closer to a full cup, which is why recipes specify sifted when they care about the difference.
Does sifting change how much powdered sugar I need?
It changes the cups and not the grams. Sifting adds air, so sifted sugar occupies more space at the same weight. If your recipe is written in grams, sifting is purely a texture step and you can do it whenever you like. If it is written in cups, the sifting instruction is part of the measurement.
Can I use powdered sugar instead of granulated?
Not cup for cup. A cup of powdered sugar weighs 113 g against 200 g for granulated, so you would be using barely over half the sugar by weight. It also contains cornstarch and has no crystals, which means it cannot aerate butter during creaming and behaves badly in cooked syrups.
Why does powdered sugar contain cornstarch?
To keep it from caking in the box. Sugar ground this fine has an enormous surface area and pulls moisture from the air, so manufacturers add roughly three percent starch as an anti-caking agent. That starch is also why powdered sugar thickens frostings as they stand and clouds a glaze slightly.
Why did my frosting stiffen after I made it?
The cornstarch is still taking up moisture. It continues hydrating for a while after mixing, so a frosting that was the right consistency in the bowl can be noticeably stiffer twenty minutes later. The remedy is a small amount of liquid worked in, not more beating, which only warms the fat.
Sources
Where the constants and formulas on this page come from. Each line names the figure it backs.
One cup of unsifted powdered sugar weighs 113 g, against 200 g for granulated and 213 g for packed brown sugar.
Ingredient Weight Chart — King Arthur Baking
The cup used for nutrition labelling is defined as 240 millilitres, the volume this density is measured against.
21 CFR 101.9(b)(5)(viii) — Nutrition labeling of food — US Government Publishing Office
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