Kitchen Scale or Measuring Cups and Spoons?

American recipes and Nutrition Facts labels speak in cups, tablespoons and teaspoons, while a kitchen scale speaks in grams. This guide explains what a cup means on a label, how much a cup of the same food can weigh, what research says about measuring by volume or by eye, and where cups and spoons are fine. It is general information for adults. For choosing a scale, see our buying guide.

What a cup means on a label

Federal rules put the household measure first and the metric amount second. Under 21 CFR 101.9, a serving is shown in a common household measure appropriate to the food, such as a cup, tablespoon, teaspoon, piece or slice, followed by the metric equivalent in parentheses, in grams for foods other than fluids. FDA's lasagna example reads "1 cup (227g)". Two details matter if you track what you eat:

• The label cup is a defined size. For labeling, a teaspoon is 5 mL, a tablespoon 15 mL and a cup 240 mL, and 1 ounce of weight counts as 28 g. NIST's conversion factors for the US customary units are 4.93 mL, 14.79 mL and 236.59 mL, so the labeling units run about 1.4% larger. That difference is small.
• The grams are the manufacturer's measurement. The rule has the gram weight rounded to the nearest whole number above 5 g, and FDA has issued guidance on determining the gram weight of a household measure. Compliance is judged against the metric amount, not the cup.

One cup, many weights

The bigger gap comes from the food. USDA FoodData Central (SR Legacy data) lists what a household measure of a food weighs:

• All-purpose flour: 1 cup, 125 g. King Arthur Baking's published chart gives 120 g for its flour.
• Granulated sugar: 200 g a cup. Brown sugar: 220 g packed or 145 g unpacked.
• Honey: 339 g a cup and 21 g a tablespoon.
• Cheddar cheese: 113 g a cup shredded and 132 g diced.
• Dry pasta: 64 g a cup of shells, 95 g of penne and 122 g of elbows.
• Cooked spaghetti: 124 g a cup loose and 151 g packed.

Those grams turn into calories quickly. At 380 kcal per 100 g, a cup of brown sugar is about 836 kcal packed and 551 kcal unpacked. At 371 kcal per 100 g, a cup of dry shells is about 237 kcal and a cup of dry elbows about 453 kcal. A recipe or app entry that says only "cup" hides gaps like these. Even for flour, two published weights for a cup, 125 g and 120 g, sit about 4% apart, and King Arthur's own chart advises weighing ingredients on a digital scale.

What research says about measuring by eye and by cup

A 2016 study in the Journal of Nutritional Science asked 67 adults to estimate the size of 42 pre-weighed foods and drinks. Of the geometrically shaped items estimated with household measures such as cups and spoons, 29% fell within 25% of the true weight and 8% within 10%. A 2020 systematic review in Nutrition Reviews looked at 334 records on portion-size estimation tools, found that only 21 compared a tool with actual amounts of food, and concluded that image-based tools were more accurate than food models and household utensils.

Both concern estimating, not carefully levelling a cup, so they do not show that measuring cups are inaccurate. They show that "about a cup" is a loose number. A Cochrane review of 72 studies, 81% of them in the USA, found that people consistently consume more food and drink when offered larger portions, packages or tableware.

Where cups and spoons are fine

• Water-like liquids. FoodData Central lists whole milk at 244 g a cup, so a liquid measuring cup is close enough for milk or broth. Read it at eye level on a flat surface. A search for liquid measuring cups on Amazon (opens in a new tab) shows the usual styles.
• Foods with few calories per gram. A cup of raw spinach is 30 g and about 7 kcal, and a cup of chopped raw broccoli is 91 g and about 31 kcal, so a loose cup changes the day's total very little.
• Recipes that forgive. Soups and stews rarely depend on exact amounts.

Spoons need more care for dense foods. FoodData Central lists 2 tablespoons of peanut butter as 32 g, about 191 kcal. If a heaped spoon held 24 g instead of a level 16 g, that would add roughly 48 kcal, and a cup of peanut butter is 258 g.

Building your own cup-to-gram list

1. Put your usual cup or spoon on the scale and press tare.
2. Fill it the way you normally do, level or heaped, packed or loose, and note the grams.
3. Write the grams on the recipe or in your tracking app, and log those grams from then on.
4. Repeat once or twice for foods that vary, such as flour, oats and shredded cheese.

A scale that switches between grams and ounces helps with recipes that give ounces: digital kitchen scales with grams and ounces on Amazon (opens in a new tab) is a search for them. An ounce on a scale is weight, and a fluid ounce on a measuring cup is volume, so a cup of water of about 8 fluid ounces weighs about 237 g, or 8.3 ounces, and other foods do not follow that.

Serving sizes change, so check the grams

NIDDK notes that FDA changed some serving sizes so labels match how much people typically eat: ice cream moved from 1/2 cup to 2/3 cup and yogurt from 8 ounces to 6 ounces. Because the cup measure can move while the food stays the same, the gram figure in parentheses is the stable number to compare. NIDDK also says the serving size is not a recommendation of how much to eat.

A middle way

1. Weigh your usual portions of staples for a couple of weeks and note how they look in your own bowl and cup.
2. Use measuring spoons for oils and spreads and a scale for dense foods: measuring cups and spoons on Amazon (opens in a new tab) is a search for sets.
3. Check again now and then, because portions drift.

Cautions

If weighing and measuring become rigid, step back. NIMH notes that some people become fixated or obsessed with weight loss, body weight or shape, and controlling their food intake, and that these may be signs of an eating disorder; talk to a health care provider if that sounds familiar. This guide is for adults. Ask a child's pediatrician before measuring or limiting a child's food.

The label on the pack is the authority on that food, and your doctor or a registered dietitian is the right person to ask about your own diet. See also our guide to scale accuracy and calibration and weighing food for tracking.