If a recipe, a packet or a scale gives you 100 g of cream of tartar and your kitchen has only cup measures, the answer is 0.69 cups, approximately. The maths is one division: 100 ÷ 144 = 0.69, because one US cup of cream of tartar weighs 144 g (spooned and levelled, USDA). Treat that as a good working figure rather than a laboratory standard, and when the dish is delicate, verify with a kitchen scale before you commit.
This page is the reverse of the usual conversion: most recipes list cream of tartar in cups and the cook wants grams, but here the recipe, the packet or the scale gives grams and the cook has only cup measures. That happens more often than people expect — imported recipes, nutrition labels, bulk packs and meal-prep plans all speak in grams, while American cup measures are what is actually in the drawer. The conversion is one division, 100 ÷ 144 = 0.69, and the table below runs the same division for the amounts that come up most often.
100 grams of cream of tartar in cups — conversion table
| Grams | Cups (approx.) |
|---|---|
| 25 g | 0.17 cups |
| 50 g | 0.35 (1/3 cups) |
| 75 g | 0.52 (1/2 cups) |
| 100 g | 0.69 cups |
| 125 g | 0.87 (7/8 cups) |
| 150 g | 1.04 cups |
| 200 g | 1.39 cups |
| 250 g | 1.74 cups |
| 300 g | 2.08 cups |
| 400 g | 2.78 cups |
| 500 g | 3.47 cups |
Read the table from left to right: find the grams you have, and the cups column tells you how much that is, approximately. A quarter of a cup is 36 g, half a cup is 72 g, and three quarters is 108 g. For amounts between the rows, divide the grams by 144: for example, 36 g is 0.25 cups, and 108 g is 0.75 cups. The same 144 g figure works in the other direction too — multiply cups by 144 to get grams — and the second table runs that calculation for the common cup fractions.
| Cups | Grams (approx.) |
|---|---|
| 1/4 cup | 36 g |
| 1/3 cup | 48 g |
| 1/2 cup | 72 g |
| 2/3 cup | 96 g |
| 3/4 cup | 108 g |
| 1 cup | 144 g |
| 1 1/2 cups | 216 g |
| 2 cups | 288 g |
How the 144 g cup is measured
The 144 g figure only holds when cream of tartar is measured the way USDA measured it: spooned and levelled. Acidic white powder left over from winemaking, and it is used for Stabilising egg whites, activating baking soda and making baking powder That matters because the measuring method is part of the number. A cup that is scooped straight from the container packs the ingredient in and weighs more than a cup that is spooned in and levelled, and for a light or powdery ingredient the gap can be 20 to 30 percent — enough to change a recipe outright.
That is why the headline number on this page is labelled approximate. USDA publishes the figure as a standard, and it is the best single number available, but your cream of tartar, your cup and your technique will all nudge it a gram or two in either direction. When the dish is forgiving — baking and seasoning — that nudge does not matter. When it is a cake, a custard or a batch of dough, weigh the cream of tartar on a kitchen scale and let the grams decide. The cup figure is a convenience for the everyday cook, not a laboratory standard, and treating it that way keeps both the recipe and the cook honest.
Worked examples with cream of tartar
A baking recipe written in grams
The dry ingredient goes into the bowl by the cup is a good place to start. 75 g of cream of tartar is 0.52 (1/2 cups), because 75 divided by 144 is 0.52. In practice that means a recipe calling for 0.52 (1/2 cups) can be weighed out as 75 g and tipped straight into a mixing bowl, with no jug to wash. The habit to build is converting once, writing the cup figure on the recipe, and then cooking from the cups — the scale only comes out for the first batch, and after that the converted recipe is a cup recipe. If the amount is awkward, round to the nearest tablespoon: one tablespoon of cream of tartar weighs about 9.0 g, so a couple of spoonfuls either way covers most rounding gaps without anyone noticing in the finished dish.
A bulk batch, halved or doubled
Scaling a recipe is where grams-to-cups conversion earns its keep. 200 g of cream of tartar is 1.39 cups, because 200 divided by 144 is 1.39. A cook who weighs the ingredient once and writes the cup figure on the recipe card never has to do the division again, and the second time the dish is made it is a cup recipe from the start. The trap is scaling the cups by eye instead: doubling a rounded cup figure doubles the rounding error too, so always scale from the grams, then convert the total, and only then round to a measuring cup that exists in the drawer.
A spice rub or seasoning blend
The third scenario is the one that catches beginners out. 350 g of cream of tartar is 2.43 cups, because 350 divided by 144 is 2.43. That looks like a lot of cream of tartar in a bowl, and it is — but the division does not care how big the number looks, and neither does the recipe. The practical move is to weigh the full amount on the scale, then measure it out in cupfuls into a mixing bowl, counting as you go, so the scale confirms the cups rather than the other way round. If the last cupful is a partial one, the table above tells you exactly how partial it should be.
Practical guidance: getting cream of tartar right
The most common mistake with cream of tartar is measuring by the wrong method. Cream of Tartar is measured spooned and levelled by USDA, and any other approach changes the weight of the cup. Scooping packs it down, tapping the cup settles it, and heaping it over the rim adds a spoonful that the recipe never asked for. Spoon it in, level it with the back of a knife, and read a liquid at eye level in a jug on a flat surface.
The second mistake is treating all cups as equal. A US cup is 236.6 ml, a metric cup is 250 ml, and an old imperial cup is different again, so a recipe that says "1 cup" without saying which cup is already ambiguous before any conversion begins. This page uses US cups throughout, and the 144 g figure belongs to a US cup of cream of tartar. If the recipe came from a metric country, check whether its cups are metric before converting, or better still, cook from the grams and skip cups entirely.
Storage matters too, because stale cream of tartar measures differently from fresh: Airtight jar, cool and dry, up to 3 years A jar that has sat open absorbs moisture or dries out, and either way the cup weight drifts from the standard. Keep the container sealed, keep it in the place the packet suggests, and replace it when it is past its best, since no conversion can fix an ingredient that has gone off.
When you have no scale at all, the cups on this page are your fallback, and they are a good one for everyday cooking. Weigh once when you can, note the cup figure that matched, and build a small personal conversion list on the inside of a cupboard door. Over a few months that list becomes more accurate for your kitchen than any published table, because it reflects your cups, your brands and your hands.
Frequently asked questions
Is 100 g of cream of tartar exactly 0.69 cups?
Approximately, yes, and the word approximately matters. The division is exact — 100 ÷ 144 = 0.69 — but the 144 g per cup figure is itself a standard average from USDA, measured spooned and levelled. A different brand, a different grind or a different measuring technique can shift a cup by a few grams, so 0.69 cups is the right working figure, and a kitchen scale is the right check when the recipe is delicate.
How do I measure 100 g of cream of tartar without a scale?
Measure 0.69 cups spooned and levelled, using a proper dry measuring cup for a dry ingredient or a liquid jug for a pourable one, and level the top with a straight edge. Do not scoop from the bag or pack the cup down unless the method says packed, because that adds weight and throws the conversion off. If you only have tablespoons, one tablespoon of cream of tartar weighs about 9.0 g, so roughly 11 level tablespoons make 100 g — a useful fallback, though a scale is still more accurate.
Can I use the same conversion for a different brand of cream of tartar?
Yes, as a starting point. The 144 g per cup figure from USDA is a standard for cream of tartar in general, and most brands land within a few grams of it. The exception is a product whose texture is very different from the standard — a coarse grind, a low-fat version or a whipped one — where the cup weight can move further. If a brand behaves oddly in a recipe, weigh it once, note the result on the packet, and use your own figure from then on.
Why do different websites give different cups for 100 g of cream of tartar?
Because they start from different cup weights. Some sites use a rounded 8-ounce cup, some use a scooped cup, and some use a different source entirely, and each choice changes the divisor in the same division. This page uses 144 g per cup (spooned and levelled, USDA) consistently, so every number here agrees with every other number here. When you compare sources, compare the cup weight they assume, not just the final answer.
Does humidity change how much 100 g of cream of tartar fills a cup?
Yes, a little. Dry powders and ground spices absorb moisture from damp air and settle more tightly, so a cup can weigh slightly more on a humid day than on a dry one, and a cup that has sat in the jar can compact under its own weight. Stir or fluff the ingredient before measuring, spoon it into the cup, and level it off — that keeps the conversion close to the 144 g standard this page uses.
Can I round 0.69 cups to a simpler fraction?
Usually, yes, and the table shows which fractions are close. 0.69 cups sits near a decimal fraction, so rounding to that is fine for a forgiving dish such as a soup, a salad or a roast. For baking, keep the decimal or weigh the grams instead, because a rounded cup in a cake or a dough can be the difference between a good rise and a dense one.