1/2 Cup Molasses in Grams
1/2 cup of molasses weighs 170 g (poured, King Arthur Baking). Thick, dark syrup left after sugar refining; strongly flavoured. All the figures on this page are approximate conversions based on the King Arthur Baking value, so when a recipe really matters, verify with a kitchen scale.
Thick, dark syrup left after sugar refining; strongly flavoured. It is used for gingerbread, baked beans, barbecue sauce and rye bread. That range of uses is part of why the conversion comes up so often: the same ingredient appears in everyday cooking and in precise baking, and the two situations demand different levels of accuracy. Knowing the weight of half a cup, rather than guessing from a measuring cup, keeps the result consistent no matter which recipe you are following.
Why weighing half a cup of molasses beats measuring it in cups
Syrups are deceptive to measure because they cling to everything: the cup, the spoon, the side of the jar. 1/2 cup of molasses weighs 170 g, but a good spoonful of that can stay behind in the measuring cup, so the amount that reaches the bowl is less than the amount you measured. Weighing the jar on a scale and pouring until the weight drops by 170 g is the trick professionals use, and it works because it measures what actually left the jar. It also keeps the washing up down, since nothing needs to be scraped out of a cup.
Molasses cups to grams conversion table
| Cups | Grams (approx.) |
|---|---|
| 1/4 cup | 85 g |
| 1/3 cup | 113.5 g |
| 1/2 cup | 170 g |
| 2/3 cup | 226.5 g |
| 3/4 cup | 255 g |
| 1 cup | 340 g |
| 1 1/2 cups | 510 g |
| 2 cups | 680 g |
| 3 cups | 1020 g |
One tablespoon of molasses weighs about 21 g, and one teaspoon about 7 g. For small amounts a scale that reads to the gram is far more reliable than a spoon, because a heaped tablespoon can weigh half as much again as a level one. The table is rounded to the nearest half gram, so the numbers are approximate by design; the half-cup figure of 170 g is the one to use when a recipe calls for half a cup.
How the weight was measured
Poured means pouring the ingredient into a liquid measuring jug on a flat surface and reading the level at eye level. Liquids level themselves, so there is no spooning or levelling involved, and the weight follows directly from the volume and the density.
The source for the 340 g per cup figure is King Arthur Baking, and the confidence in the value is high. King Arthur Baking publishes a standard ingredient weight chart that recipe developers use as a reference, and this page follows it exactly rather than averaging across sources, because an average of two different measuring methods is a number that matches nobody's cup.
Because molasses is measured poured, the weight per cup is stable from one kitchen to the next, and the 170 g figure for half a cup is a reliable default. Small differences in brand or temperature shift it by only a gram or two, which is far below the threshold that changes a recipe.
All the figures on this page are approximate conversions. When a recipe really matters, verify with a kitchen scale: weigh the ingredient directly into the bowl on a tared scale and trust that number over any cup.
Worked examples
A gingerbread or spice cake
A gingerbread recipe calling for 1/2 cup of molasses needs 170 g. Weigh the mixing bowl, tare the scale, and pour until it reads 170 g: the syrup goes in cleanly, nothing sticks to a cup, and the cake gets exactly the moisture and sweetness the recipe intended.
Halving a glaze
Halving a glaze that uses 1 cup of molasses leaves 1/2 cup, or 170 g. A glaze is unforgiving about ratios, so weighing the half-cup keeps it glossy and pourable instead of grainy or watery.
Sweetening a dressing
A salad dressing needing 1/4 cup of molasses takes about 85 g. Pouring that small amount from a jug is fiddly, but a scale reads it instantly and the dressing stays balanced.
When this conversion matters most
This conversion matters most where molasses is a structural ingredient: gingerbread, candy, pecan pie and glazes all depend on the exact amount of syrup for their set, their moisture and their sweetness. It also matters when you substitute one syrup for another, because syrups weigh differently per cup and a cup-for-cup swap changes the recipe. Swap by weight, using the 170 g figure for 1/2 cup, and the substitution stays honest.
Common mistakes with molasses
- Measuring a sticky syrup in a dry cup. The syrup clings to the cup and a spoonful stays behind. Weigh it instead: tare the bowl, pour to 170 g, and everything you measured reaches the batter.
- Swapping syrups cup-for-cup. Syrups weigh differently per cup, so a cup-for-cup swap changes sweetness and moisture. Swap by weight using the figures on this site.
- Pouring over the bowl. A drip of syrup into the batter is easy and invisible. Pour over the jar or the sink, or weigh directly on a tared scale.
- Forgetting the syrup is liquid too. molasses counts towards the liquid in a recipe, so adding it on top of the full liquid measure makes a batter wet. Reduce other liquids if the recipe tells you to.
Storage and handling
Airtight jar, cool and dark, up to 1 year. Keeping molasses stored properly also keeps its weight per cup stable: an ingredient that has absorbed moisture from the air weighs more per cup than a dry one, so good storage is not just about freshness, it is about measurement accuracy too. If a container has been open for months in a humid kitchen, the first thing to do before a precise bake is to weigh the ingredient rather than trusting the cup.
Frequently asked questions
How many grams is 1/2 cup of molasses?
1/2 cup of molasses weighs 170 g, measured poured according to King Arthur Baking. That is the figure to use when converting a recipe from cups to grams, and it is the value the conversion table on this page is built on.
How do I measure molasses without a scale?
Poured means pouring the ingredient into a liquid measuring jug on a flat surface and reading the level at eye level. Liquids level themselves, so there is no spooning or levelling involved, and the weight follows directly from the volume and the density. That gives the closest result to 170 g per half-cup, but it is still an estimate: the honest answer is that a scale is the only way to know the exact weight, and a basic digital kitchen scale costs less than a bag of good flour.
Can I swap molasses for another syrup cup-for-cup?
Not reliably. Syrups weigh different amounts per cup and have different sweetness and moisture, so a cup-for-cup swap changes the recipe. Swap by weight instead: 1/2 cup of molasses is 170 g, so use the same weight of the other syrup and expect a slightly different flavour.
What is molasses used for?
Gingerbread, baked beans, barbecue sauce and rye bread. Thick, dark syrup left after sugar refining; strongly flavoured.
How do I measure molasses without a scale?
Pour it into a liquid measuring jug at eye level and read the meniscus at 1/2 cup, then scrape the jug out thoroughly with a spatula. Or grease the cup lightly first so the syrup slides out. Both work, but neither is as accurate as weighing 170 g on a scale.
How should I store molasses?
Airtight jar, cool and dark, up to 1 year. Good storage keeps the ingredient fresh and keeps its weight per cup consistent, because moisture absorbed from the air adds grams that the recipe did not ask for.
Related conversions
Use the sugar substitute converter or the cups to grams converter for instant answers, or browse the cups to grams hub for the full ingredient list. Related pages: Molasses in cups to grams, 1/2 cup honey in grams, 1/2 cup maple syrup in grams, 1/2 cup corn syrup in grams. More tools: cups to grams converter, grams to cups converter, recipe scaler. See also our disclaimer about approximate conversions.