Marshmallow Fluff: Jar Sizes in Cups & vs Marshmallows
1 cup of marshmallow fluff (also called marshmallow creme) weighs about 80 g. Most people arrive here holding a packet, so the chart below runs from grams to cups: 100 g is about 1 1/4 cups, and 340 g is about 4 1/4 cups.
💡 Tip: Fluff is extremely light (only ~80 g per cup), so a small jar holds far more cups than its weight suggests — grease the cup and spoon to get it back out
How many cups is a jar of marshmallow fluff?
Fluff (and marshmallow creme) is sold by weight but it's mostly whipped air, so it's very light — about 80 g per cup. That means a small jar goes a long way:
| Jar size | Cups (approx) |
|---|---|
| 7 oz (198 g) | ~2½ cups |
| 7.5 oz (213 g) | ~2⅔ cups |
| 13 oz (369 g) | ~4½ cups |
| 16 oz (454 g) | ~5⅔ cups |
Is marshmallow fluff the same as marshmallows?
Marshmallow fluff and marshmallow creme are the same thing — a spreadable whipped marshmallow (the name just changes by brand and region). Whole marshmallows are not a clean 1:1 swap: they hold their shape and set firmer. As a rough guide for melting into fudge or frosting, a 7 oz jar of creme stands in for about 4 cups of mini marshmallows, but the creme stays softer and won't set as firmly. For s'mores or toppings they aren't interchangeable.
Marshmallow Fluff by weight: grams to cups
| Grams | Amount | Ounces |
|---|---|---|
| 15 | 3 tbsp | 0.53 |
| 20 | 1/4 cup | 0.71 |
| 30 | 3/8 cup | 1.06 |
| 50 | 5/8 cup | 1.76 |
| 100 | 1 1/4 cups | 3.53 |
| 150 | 1 7/8 cups | 5.29 |
| 200 | 2 1/2 cups | 7.05 |
| 250 | 3 1/8 cups | 8.82 |
| 300 | 3 3/4 cups | 10.6 |
| 340 | 4 1/4 cups | 12 |
| 450 | 5 5/8 cups | 15.9 |
Marshmallow Fluff cup measurements, in grams
| Cups | Grams | Ounces |
|---|---|---|
| 1/8 | 10 | 0.35 |
| 1/4 | 20 | 0.71 |
| 1/3 | 26.7 | 0.94 |
| 1/2 | 40 | 1.41 |
| 2/3 | 53.3 | 1.88 |
| 3/4 | 60 | 2.12 |
| 1 | 80 | 2.82 |
| 1 1/2 | 120 | 4.23 |
There are 16 tablespoons in a cup, so one tablespoon of marshmallow fluff weighs roughly 5 g — and a teaspoon 1.67 g.
How marshmallow fluff compares with other syrups & spreads
At 80 g per cup, marshmallow fluff is the lightest of the 10 syrups & spreads charted on this site. At the other end of the range, honey weighs 340 g — 325% more for the very same cup.
That gap matters when you substitute by volume: use a cup of almond butter where the recipe wanted marshmallow fluff and you have added about 176 g extra — 220% more than intended. Weighing instead of scooping removes the problem.
Frequently asked questions
- How many grams is a tablespoon of marshmallow fluff?
- 1 tablespoon of marshmallow fluff is about 5 grams (a teaspoon is roughly 1.67 g).
- How many cups is a 7 oz jar of marshmallow fluff?
- About 2½ cups. Fluff is mostly air (around 80 g per cup), so even a small 7–7.5 oz jar holds roughly 2½–2⅔ cups.
- Is marshmallow fluff the same as marshmallow creme?
- Yes — marshmallow fluff and marshmallow creme are the same product; the name just varies by brand and region.
- Can I use marshmallows instead of marshmallow fluff?
- Not as a direct swap. Melted, about 4 cups of mini marshmallows roughly replaces a 7 oz jar of creme in fudge or frosting, but the result sets firmer. For spreading or s'mores they aren't interchangeable.
- How many grams is 1 cup of marshmallow fluff?
- 1 cup of marshmallow fluff weighs only about 80 grams because it's mostly whipped air.
- How many cups is 100g of marshmallow fluff?
- 100 grams of marshmallow fluff is about 1 1/4 cups.
- How many ounces is 1 cup of marshmallow fluff?
- About 2.82 oz. Note that is weight, not fluid ounces — a cup is always 8 fl oz whatever is in it.
- Why do my numbers differ slightly?
- Viscosity depends on temperature. Warm syrup flows into the corners of a cup and cold syrup leaves gaps behind, and a sticky film always stays in the cup — which is why weighing straight into the bowl is easier.