5 lb bag of flour is how many cups: Why Your Recipe Might Be Failing

You're standing in the baking aisle, staring at that heavy paper sack, and you've got a single question: 5 lb bag of flour is how many cups exactly? It seems like it should be a simple math problem. You take the total weight, divide by the cup weight, and boom—you have your answer. But if you’ve ever pulled a cake out of the oven only to find it has the structural integrity of a brick, you know baking isn't always that kind.

The short answer is about 18 to 19 cups.

That is the "textbook" answer. If you use the standard USDA measurement where one cup of all-purpose flour weighs 125 grams, a 5-pound bag (which is 2,268 grams) yields roughly 18.1 cups. But honestly? If you just scoop that flour straight from the bag with a measuring cup, you might only get 15 or 16 cups. Why? Because flour packs down. It settles. It gets dense during shipping.

The Heavy Truth About Flour Weight

Flour is temperamental. It’s not like water. A cup of water is always going to weigh the same because liquids don't compress. Flour is full of tiny air pockets. When a 5 lb bag of flour sits on a grocery store shelf for three weeks, the weight of the flour at the top crushes the flour at the bottom.

Most professional bakers, like those at King Arthur Baking Company, will tell you that their "standard" cup of flour weighs 120 grams. If you follow their math, that 5 lb bag of flour is how many cups? About 18.9 cups.

However, if you look at a brand like Gold Medal, they often suggest a cup is closer to 130 grams if you're a "heavy-handed" scooper. That brings your total bag yield down significantly. This discrepancy is why your grandma’s "dip and sweep" method might result in a totally different cookie than your neighbor’s "spoon and level" technique.

Does the Brand Actually Matter?

It really does. Not all all-purpose flour is created equal. Protein content varies. For instance, King Arthur All-Purpose Flour has a protein content of about 11.7%. Compare that to White Lily, a Southern favorite for biscuits, which is much lower, usually around 8% or 9%.

Lower protein flour is often milled finer. It’s fluffier. It’s softer. If you’re measuring a 5 lb bag of flour of a softer variety, you might find it occupies more volume because it doesn't clump as aggressively as high-protein bread flour.

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How You Measure Changes Everything

Let's talk about the "Scoop." Most people just shove the measuring cup into the bag. You're basically packing the flour in like you're making a sandcastle. When you do this, you can easily fit 150 grams of flour into a 1-cup measure.

1. The Dip and Sweep: You dunk the cup, you hit the side to level it, and you scrape off the top. This is the densest way to measure. You'll run out of your 5 lb bag way faster than the recipe predicts.
2. The Spoon and Level: You gently spoon flour into the cup until it overflows, then level it with a knife. This gets you closer to that 120-125 gram "sweet spot."
3. The Sift: You sift the flour first, then measure. This is the light-as-air method.

If you use the spoon and level method, you'll consistently get around 18 cups from your bag. If you're a "dipper," you might only get 15. That’s a three-cup difference! That is enough to ruin three separate batches of loaves.

Why 5 lb bag of flour is how many cups Matters for Your Budget

Inflation has hit the pantry hard. In 2026, we’re seeing price fluctuations that make every gram count. When you’re meal prepping or running a small home-based bakery, knowing the yield of your raw materials is vital for your margins.

If a recipe calls for 4 cups of flour, and you're getting 18 cups per bag, you can get 4.5 batches of that recipe per bag. But if your measuring technique is off and you're only getting 15 cups, you’re down to 3.75 batches. Over a month of baking, that’s several bags of flour wasted just because of air and pressure.

Volume vs. Mass: The Eternal Battle

In the United States, we are obsessed with cups. It’s a legacy system. In Europe and much of the professional culinary world, everything is grams.

Grams don't lie.

A 5 lb bag is always 2,268 grams. Period. It doesn't matter if the flour is humid, if it’s been sitting in a hot car, or if you’ve shaken the bag. If you use a digital scale, the question of "how many cups" becomes irrelevant because you are measuring the actual matter, not the space it occupies.

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Humidity: The Silent Variable

Have you ever noticed your flour feels "clumpy" in the summer? Flour is hygroscopic. It sucks moisture right out of the air. In a humid kitchen in New Orleans, your flour will weigh more than it does in a dry kitchen in Denver.

If your flour has absorbed 2% of its weight in water from the air, that 5 lb bag still weighs 5 lbs, but some of that weight is now water instead of wheat. This means you actually have less flour in the bag than you did when it was packaged in a climate-controlled factory.

Different Flour Types and Their Yields

Not all 5 lb bags are all-purpose.

• Whole Wheat Flour: It’s denser. The bran and germ are still in there. A cup usually weighs about 130-140 grams. You’ll get fewer cups out of a 5 lb bag—usually around 16 to 17 cups.
• Bread Flour: It’s high in protein and can be slightly heavier than all-purpose. Expect about 17 to 18 cups.
• Cake Flour: This is the light stuff. It’s often sold in smaller boxes, but if you had a 5 lb bag, you’d be looking at 20+ cups because it’s so finely milled.

Stop Guessing and Start Weighing

The most actionable thing you can do right now? Buy a $15 digital kitchen scale.

You can find them at any big-box store. Set it to grams. Place your bowl on the scale, hit "tare" to zero it out, and pour your flour in. No more dirtying five different measuring cups. No more wondering if you packed the cup too tight.

If a recipe says "1 cup of flour," assume 125 grams. If it’s a King Arthur recipe, use 120 grams. If it’s a vintage recipe from a 1950s cookbook, they were likely using the "dip and sweep" method, so you might want to lean closer to 135 grams.

Storage Tips to Keep Your Flour Consistent

Don't leave your flour in the paper bag once it's open. Paper is porous. It lets in bugs, moisture, and odors from your kitchen. Move that 5 lb bag into an airtight plastic or glass container.

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This keeps the moisture level stable. It also prevents the flour from "settling" as much. When you store flour in a tall, narrow container, the pressure at the bottom is higher than if you store it in a wide, shallow bin.

The "Fluff" Rule

If you refuse to use a scale—and I get it, some people just love the ritual of the cup—then you must adopt the fluff rule. Before you measure, take a fork or a whisk and stir the flour in your container. This introduces air back into the powder. Then, use the spoon and level method. This is the only way to get your cup count close to the 18-19 cup average that manufacturers intend.

Summary of Yields by Method

To make this easy to visualize, think of your 5 lb bag of flour as a bank account.

If you measure by weight (125g/cup), you have 18.1 cups to spend.
If you measure by "Spoon and Level," you have about 18 to 19 cups.
If you measure by "Dip and Sweep," you only have 15 to 16 cups.
If you sift first, you might have up to 21 cups.

Your choice of tool and technique literally changes the quantity of food you can produce.

Next Steps for the Home Baker

First, go check your current bag of flour. Is it tucked away in a humid pantry? Move it to a cool, dry spot.

Second, if you're halfway through a recipe and realize you're short on flour, don't just assume a second bag will behave the same way. Always fluff the new bag before measuring to ensure you aren't adding way too much flour to your dough.

Finally, start a "baking log." It sounds nerdy, but it works. Note the brand of flour, the method you used to measure, and how the final product turned out. If your bread is always too dry, you’re likely measuring too much flour—meaning you're getting fewer cups out of that 5 lb bag than you should. Lowering your "cup weight" by just 10 grams can be the difference between a dense loaf and a bakery-quality masterpiece.