1 Cup Molasses in Grams
1 cup of molasses weighs 340 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.
Why weighing molasses beats measuring it in cups
Most people think of sugar as a sweetener only, but in baking it is a structural ingredient. It competes with flour for water, delays gluten development, and caramelises to give colour and flavour. That is why the same cake can come out pale and tough one time and golden and tender the next: the sugar was measured differently. A kitchen scale turns a vague cup into an exact number, and once you bake with grams you will notice how much more consistent your results become.
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.
Molasses cups to grams conversion table
| Cups | Grams | Tablespoons (approx.) |
|---|---|---|
| 1/4 cup | 85 g | 5.3 g |
| 1/3 cup | 113.3 g | 7.1 g |
| 1/2 cup | 170 g | 10.6 g |
| 2/3 cup | 226.7 g | 14.2 g |
| 3/4 cup | 255 g | 15.9 g |
| 1 cup | 340 g | 21.2 g |
| 1 1/2 cups | 510 g | 31.9 g |
| 2 cups | 680 g | 42.5 g |
| 3 cups | 1020 g | 63.8 g |
| 4 cups | 1360 g | 85 g |
The tablespoon column is a bonus for recipes that call for a spoonful or two: one tablespoon of molasses weighs about 21.2 g. Remember that a cup is 16 tablespoons, so the numbers in the table are just the cup weight divided by 16, rounded to one decimal place. 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.
How the weight was measured
Poured means the ingredient is a liquid or a free-flowing syrup, so it is measured in a liquid measuring jug with a spout, read at eye level. Liquids settle flat, so there is no packing or levelling to worry about, but a sticky liquid will cling to the jug, which is one more reason to weigh it instead.
The source for the 340 g 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.
Worked examples
A caramel sauce for a dessert
A caramel that starts with 1 1/2 cups of molasses needs 510 g. Caramel is unforgiving about ratios, and an extra 20 g of sugar changes how fast it colours and how bitter it gets. Weigh the sugar, and the caramel behaves predictably.
Halving a cake recipe
Halving a cake that uses 2 cups of molasses means 1 cup, or 340 g. It is tempting to halve by eye, but sugar is a structural ingredient in cake, so weighing 340 g keeps the crumb tender and the crust golden.
Sweetening a large batch of lemonade
A lemonade recipe for a party that calls for 2 cups of molasses needs 680 g. When you are scaling up for a crowd, cups multiply the error, so weighing 680 g gives the same sweetness as the single batch you tested.
When this conversion matters most
This conversion matters most when a recipe depends on sugar for more than sweetness. In candy making, sugar is heated to a precise temperature, and the amount decides whether you get soft fudge or hard toffee. In baking, sugar holds moisture and delays setting, so the wrong amount changes the bake time as well as the flavour. It also matters for anyone tracking sugar intake, because weighing gives a true number while a cup can hide an extra 20 g.
Common mistakes with molasses
- Heaping the cup. A heaped cup of sugar can add 15 to 20 g. Always level the top with the back of a knife.
- Packing granulated sugar. Granulated sugar should be spooned and levelled, not packed. Packing is only for brown sugar, where it is part of the measurement.
- Swapping sugars cup for cup. Brown sugar, caster sugar and powdered sugar all weigh differently per cup, so swapping them by volume changes the recipe. Convert by weight instead.
- Forgetting that sugar is hygroscopic. Sugar absorbs moisture from the air, so a cup measured on a humid day can weigh slightly more. Keep sugar sealed and weigh it when precision matters.
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 a sealed container is not just about freshness, it is about measurement accuracy too. If a bag 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 cup of molasses?
1 cup of molasses weighs 340 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 the ingredient is a liquid or a free-flowing syrup, so it is measured in a liquid measuring jug with a spout, read at eye level. Liquids settle flat, so there is no packing or levelling to worry about, but a sticky liquid will cling to the jug, which is one more reason to weigh it instead. That gives the closest result to 340 g per 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.
Does molasses always weigh the same per cup?
No. Brand, grind, moisture and how settled the container is all shift the weight by a few grams, and for flour the swing can be 20 g or more. The 340 g figure is the standard King Arthur Baking value for molasses measured poured, and it is the right default, but when a recipe is precise, weigh the ingredient and trust the scale over the cup.
Can I use the same conversion for a different brand of molasses?
Yes, as a starting point. The 340 g figure is a standard average for molasses, and most brands sit within a few grams of it. If you bake with one brand all the time, weigh one cup of it once and note the number on the bag, and you will have a conversion tuned to your own kitchen.
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.
What is molasses used for?
Gingerbread, baked beans, barbecue sauce and rye bread. Thick, dark syrup left after sugar refining; strongly flavoured.
Related conversions
Use the cups to grams converter or the grams to cups converter for instant answers, or browse the cups to grams hub for the full ingredient list. Related pages: Granulated Sugar in cups to grams, Brown Sugar in cups to grams, Honey in cups to grams. More tools: cups to grams converter, grams to cups converter, sugar substitute converter, weight converter. See also our disclaimer about approximate conversions.