The Gist

The carbohydrate factor of a food is how much of that food's weight is carbohydrate.

If I portion out 100 grams of peas, for example, that's about 12 grams of carbs. Twelve percent. 0.12. That's the carb factor for peas: 0.12.

Count Versus Volume Versus Weight

If I asked you the carbs in an apple, you could take a few different approaches to give me an answer.

The simplest approach is counting. Carbs per thing. One apple has 25 grams of carbs. In fact, if you Google "carbs in an apple" as I'm writing this, that's what appears at the top, in big bold letters: "25 g".

There's also the volume approach. Say a cup of apple slices is 15 grams of carbs. Cut up the apple and measure and it's... I guess maybe two and a half cups? So that'd be 37.5 grams.

Then there's weight, using carb factors. Put the apple (or the slices) on a food scale. 223 grams. Multiply that by the carb factor, 0.14, for a total carb count of 31.2 grams.

Weight gives a more accurate measure than volume or count. Counting doesn't take into account size variation (or at best makes it very subjective — like "this apple is... medium"). Volume is challenging for anything that isn't a liquid. For the apple slices, for instance, it doesn't account for the random amount of space between the slices in the cup.

Weight can be a problem, too, sometimes, but it's not too hard to work around. Thinking of the apple: You're probably not going to eat the core, right? But you can put that uneaten part back on your scale, weigh it, and subtract that amount of weight.

It's Pretty Easy

With just a little bit of practice, weighing food and using carb factors can significantly improve the accuracy of your carb counts.

The information we need to get the carb factor for just about any food is within reach. For whole foods (think apples, oranges, broccoli), we have decent reference information available in our carb factor browser.

For packaged foods, you can often use the Nutrition Facts labels. They won't tell you the carb factor, but if they tell you the weight of the serving in grams and the grams of carbs, you can just divide to get the carb factor. Carb weight over total weight.

What About Grandma's Brownies?

It's even pretty easy to get a carb factor for a home recipe as you cook it. If you weigh the ingredients that contain carbs as you cook, then weigh the finished recipe, you can calculate the carb factor: the total carb weight over the total weight.

Even Easier

Our mission at is to make it easier to count carbs. Can't computers do some of this for us? They're better at math than us. And better at keeping track of stuff. Right?

We've built a browser for carb factors, which we use every day as we measure our son's plate. We've also created a cheat sheet to keep in the kitchen, for reference for some of the formulas.

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We're working on some other ideas, too. Our email list is the best way to be notified when we launch something new.