How Much Is a Cup of Flour in Grams?

If you want to use weights when baking and the author of a recipe doesn’t give you a weight for their flour, my testing shows that you should use 128 grams for a cup of all-purpose flour. That’s the average across four brands of flour that I weighed using methods that I describe here in order to figure out how much a cup of flour weighs in grams.

Why Use Weights for Measuring Flour

Working with weights is important if you want to be able to convert American recipes over to the metric system (converting flour from cups to grams). It’s also important if you want to break down a recipe to see the ratios of different ingredients – you should always do that by weight. Finally, using weights let you scale recipes up or down more easily and accurately.

Testing Methodology

If you do a Google search, you may find yourself on the Instructables page that says that a cup of all-purpose flour weighs 120 grams. Allrecipes says one cup of flour is 128 grams. Joy of Baking weighs in, calling one cup of flour 130 grams. Why is there a discrepancy, what number should you be using, and does it matter at all? I weighed 192 cups of flour to figure out how much a single cup of flour weighs!

I decided to look at three different factors that could cause weight variation: the method of getting the flour into the measuring cup, the brand of flour, and the type of measuring cup.

This is a long post, so grab a drink and get ready. First, I share my findings. Then, I tackle the important issue of whether the difference in weight matters. At the end, I summarize all of my conclusions (skip to that section if you are short on time).

How to Fill a Measuring Cup

There are two main ways that people fill their measuring cups.

I’m calling the first method “The Dip”. This is where you dip your measuring cup right into the bag or jar of flour.

The second method is “The Scoop”. In this method, you use a scoop to pour flour from the bag or jar into your measuring cup.

In both methods, it’s important to level off the top of the measuring cup after it is full.

I ran 72 tests on each method using different brands of flours and measuring cups. Here are the averaged results:

Perhaps more telling is the difference in standard deviation between The Dip and The Scoop. As a quick math refresher, the standard deviation is a measure that is used to quantify the amount of variation in set of data values. A standard deviation of 0 would mean that I got the exact same answer when I did things the same way. What I found was that the standard deviation for The Dip was 2.43 grams and the standard deviation for The Scoop was 1.93 grams. Using The Scoop yields more consistent results.

Differences in Flour Brands

For this project, I looked at four different brands of flour: King Arthur Flour, 365 Everyday Value Organic (Whole Foods’ house brand), Gold Medal, and Pillsbury.

When calculating the brand results, I used an average of measures taken using The Dip and the Scoop Method with a variety of measuring cups for each flour brand. The results are as follows:

That’s a 7.3% difference between Pillsbury and King Arthur Flour!

Differences in Measuring Cups

Will you get the same result using any measuring cup? It looks like the answer is “no”.

The difference in standard deviation is also striking here. The yellow cup’s standard deviation was 2.80 grams, the blue cup’s was 2.05 grams, and the pink striped cup’s was 1.68 grams. I attribute this to the round shape of the striped cup and the fact that it has less of a rim. This makes it easier to level the cup.

Using a Liquid Measuring Cup

I know that some of you use a liquid measuring cup to measure dry ingredients. I tried this and found the standard deviation was 8.76 grams! Because you can’t level a liquid measure, it is nearly impossible to get an accurate result using one. Don’t do it.

Warning: Never use a liquid measuring cup to measure dry ingredients!

Do Small Weight Differences Matter?

In short, a difference in weight can matter greatly; it depends upon your recipe.

The highest weight that I measured for a cup of all-purpose flour was 144 grams (King Arthur Flour using The Dip) and the lowest weight was 124 grams (Pillsbury flour using The Scoop). That’s a 20 gram difference. It sounds like a lot, but does it really matter? I wanted to know, so I baked two loaves of bread.

I used a scale to measure all of the ingredients. I used 124 grams of flour in one loaf and 144 grams in the other. I kept everything else exactly the same.

As the loaves were going through their second rise, I already had my answer.

The loaf on the left used the higher measurement and the loaf on the right used the lower measurement. Everything else was the same. Wow!

Here’s how the two loaves looked after the bake. (For more on this, King Arthur Flour has a fabulous post about how small differences in ingredients can significantly affect bread baking.)

In bread baking, flour is the main ingredient and interacts with the yeast and the liquid. I wondered if the difference would be as prominent in cupcakes where flour is just one of many ingredients.

The chocolate cupcake on the left used the higher weight number and the one on the right used the lower weight number. If you see a difference, let me know. To me, they are basically identical and they were also identical in taste.

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