Cooking Measurement Converter

How it works

There are two kinds of conversion in the kitchen, and they behave very differently.

Volume to volume, or weight to weight, is exact. U.S. customary units are defined in terms of metric ones. NIST gives 1 U.S. fluid ounce = 29.5735295625 mL, and from that: 1 tablespoon = 1/2 fl oz = 14.787 mL, 1 teaspoon = 1/3 tablespoon = 4.929 mL and 1 cup = 8 fl oz = 236.588 mL. For weight, the avoirdupois ounce is exactly 28.349523125 g and the pound exactly 453.59237 g. Converting 3 tablespoons to teaspoons, or 8 ounces to grams, needs no information about the ingredient at all.

Volume to weight depends on the ingredient. To go from cups to grams you need the ingredient's density — how many grams fit in a cup:

milliliters = amount × size of unit in mL
grams = milliliters × (grams per cup ÷ 236.588)

The calculator converts whatever you enter into milliliters and grams first, then expresses the result in every other unit, so all the rows in the result table are consistent with each other.

Where the ingredient weights come from

Grams-per-cup values come from two published references. Where the U.S. Department of Agriculture's FoodData Central lists a household cup weight for the food, we use it, with its FDC ID so you can check it. For baking ingredients measured the way most home bakers do — flour spooned into the cup and leveled, brown sugar packed — we use the King Arthur Baking ingredient weight chart, which is based on test-kitchen weighing.

Two flour options are offered on purpose. King Arthur weighs a cup of all-purpose flour at 120 g; USDA's portion data lists 125 g. Neither is wrong: the difference comes from how the cup is filled. Scooping the cup straight into the bag compacts flour and can add 20% or more, while sifting first lowers the weight. That spread is the main reason serious bakers prefer recipes written in grams.

Water is a useful anchor: at room temperature it weighs very close to 1 gram per milliliter, so a cup of water is about 237 g and a tablespoon about 15 g. Liquids such as milk are slightly denser than water; oils are lighter, which is why a cup of oil weighs about 218 g; syrups like honey are much heavier at around 339 g per cup.

Cups and spoons around the world

This converter uses U.S. customary measures. Other systems differ slightly, which matters most for recipes with large volumes:

• U.S. customary cup: 236.6 mL — the standard in American cookbooks and on measuring cups sold in the U.S.
• U.S. nutrition-label cup: 240 mL. FDA rules for nutrition labels (21 CFR 101.9) round household measures to 240 mL per cup, 15 mL per tablespoon and 5 mL per teaspoon.
• Metric cup: 250 mL, used in Australia, New Zealand, Canada and South Africa. A metric cup is about 6% larger than a U.S. cup.
• Australian tablespoon: 20 mL (4 teaspoons), compared with about 15 mL in the U.S. and U.K.
• Imperial (U.K.) fluid ounce and pint: 28.4 mL and 568 mL, compared with 29.6 mL and 473 mL in the U.S.

For a recipe calling for one or two cups, these differences rarely matter. For a recipe written for metric cups that uses six cups of stock, the gap is about 80 mL.

Tips for accurate measuring

• Weigh when you can. A digital kitchen scale removes the biggest source of error — how densely a cup is filled. Most scales switch between grams and ounces.
• Spoon and level dry ingredients. Stir flour to loosen it, spoon it into the cup without tapping, then sweep the top flat with a knife.
• Use liquid measures for liquids. Read a clear jug at eye level on a flat counter. Dry cups are meant to be filled to the brim and leveled.
• Don't mix systems mid-recipe. Pick grams or cups and stay with it, because the rounding in each system was chosen to keep that recipe's proportions right.
• Remember "ounces" can mean two things. Fluid ounces measure volume; ounces on a scale measure weight. They only line up for water and liquids of similar density.

Measuring for nutrition tracking

Nutrition databases list values per 100 g or per household measure. Because a cup of flour can vary by 20% depending on how it's filled, food weights are more reliable than volumes when you're counting calories. If you enter an ingredient in the Recipe Calories per Serving Calculator, this converter can turn a recipe's cups into the grams it needs.

Worked examples

Example 1: 1 cup of all-purpose flour in grams and ounces

Using King Arthur's 120 g per cup: 1 cup = 120 g. 120 ÷ 28.3495 = 4.23 oz. With USDA's 125 g per cup the answer is 125 g, or 4.41 oz.

Example 2: 250 g of granulated sugar in cups

250 g ÷ 200 g per cup = 1.25 cups (1 1/4 cups). In milliliters: 1.25 × 236.588 = 296 mL.

Example 3: 2 tablespoons of butter in grams

2 tbsp = 2/16 cup = 0.125 cup. 0.125 × 227 g = 28.4 g — about 1 ounce, or a quarter of a 113 g stick.

Example 4: 3 tablespoons to teaspoons

Volume to volume needs no density: 3 × 3 = 9 tsp (44.4 mL).

Limitations

• Volume-to-weight results are only as good as the density: settled, sifted or packed ingredients weigh different amounts.
• Densities are for the ingredient as listed; chopped, melted, cooked or whipped versions differ.
• Uses U.S. customary cups and spoons, not metric, imperial or Australian measures.
• Values are rounded for display; the exact figure is used internally.

Who should not rely on this calculator

This is a measuring aid. If you need precise amounts for a medical diet, infant formula or medication, follow the instructions from your clinician or the product label and use the measuring device provided — never kitchen spoons for medicine.