The US customary system uses a hierarchy of volume units that are related to each other by fixed ratios. Understanding these relationships makes it easy to scale recipes and convert between units without constantly looking up conversion factors.
The most common conversion cooks need is between US volume units and metric units (milliliters and liters). Here is a comprehensive reference:
| US Unit | Milliliters (mL) | Liters (L) | Metric Equivalent |
|---|---|---|---|
| 1/8 tsp | 0.616 mL | — | ≈ 0.6 mL |
| 1/4 tsp | 1.232 mL | — | ≈ 1.25 mL |
| 1/2 tsp | 2.464 mL | — | ≈ 2.5 mL |
| 1 tsp | 4.929 mL | — | ≈ 5 mL |
| 1 tbsp | 14.787 mL | — | ≈ 15 mL |
| 1 fl oz | 29.574 mL | 0.0296 L | ≈ 30 mL |
| 1/4 cup | 59.147 mL | 0.0591 L | ≈ 60 mL |
| 1/3 cup | 78.863 mL | 0.0789 L | ≈ 79 mL |
| 1/2 cup | 118.294 mL | 0.1183 L | ≈ 118 mL |
| 2/3 cup | 157.725 mL | 0.1577 L | ≈ 158 mL |
| 3/4 cup | 177.441 mL | 0.1774 L | ≈ 177 mL |
| 1 cup | 236.588 mL | 0.2366 L | ≈ 237 mL |
| 1 pint (2 cups) | 473.176 mL | 0.4732 L | ≈ 473 mL |
| 1 quart (4 cups) | 946.353 mL | 0.9464 L | ≈ 946 mL |
| 1/2 gallon | 1,892.706 mL | 1.8927 L | ≈ 1.89 L |
| 1 gallon | 3,785.412 mL | 3.7854 L | ≈ 3.79 L |
One of the most confusing aspects of volume conversion is that UK (imperial) and US customary measurements share the same names but have different volumes. This is particularly important when using older British recipes:
| Unit | US Volume | UK Volume | Difference |
|---|---|---|---|
| 1 teaspoon | 4.929 mL | 5.919 mL | UK is 20% larger |
| 1 tablespoon | 14.787 mL | 17.758 mL | UK is 20% larger |
| 1 fluid ounce | 29.574 mL | 28.413 mL | US is 4% larger |
| 1 cup | 236.588 mL | 284.131 mL | UK is 20% larger |
| 1 pint | 473.176 mL | 568.261 mL | UK is 20% larger |
| 1 quart | 946.353 mL | 1,136.523 mL | UK is 20% larger |
| 1 gallon | 3,785.412 mL | 4,546.090 mL | UK is 20% larger |
Note that for teaspoons and tablespoons, the UK version is larger, while for fluid ounces, the US version is larger. This discrepancy arises from historical differences in how the units were standardized. Modern UK recipes typically use metric units (milliliters), so this is mainly an issue with older recipes.
Australia and New Zealand use a standardized tablespoon of 20 mL (4 teaspoons), which is larger than both the US (14.787 mL) and UK (17.758 mL) tablespoon. If you are using an Australian recipe with US measuring spoons, you will need to use 4 US teaspoons (19.716 mL) to approximate 1 Australian tablespoon.
While volume measurements work reasonably well for liquids, they are less reliable for dry ingredients because of how densely the ingredient packs into the measuring cup. For example, a cup of sifted flour weighs about 120 grams, while a cup of unsifted flour can weigh 140 grams or more. This is why professional bakers prefer weight measurements.
However, when using volume measurements, it is important to use the correct type of measuring cup:
Here are some of the most frequently needed volume conversions for baking:
| From | To | Conversion |
|---|---|---|
| 1 cup | tablespoons | 16 tbsp |
| 1 cup | teaspoons | 48 tsp |
| 1/2 cup | tablespoons | 8 tbsp |
| 1/3 cup | tablespoons | 5 tbsp + 1 tsp |
| 1/4 cup | tablespoons | 4 tbsp |
| 1/8 cup | tablespoons | 2 tbsp |
| 1 pint | cups | 2 cups |
| 1 quart | cups | 4 cups |
| 1 gallon | cups | 16 cups |
| 1 liter | cups (US) | 4.227 cups |
| 1 liter | fluid ounces | 33.814 fl oz |
| 1 cup (US) | milliliters | 237 mL |
When scaling a recipe, volume conversions can help you find the right measuring tool. For example, if you are doubling a recipe that calls for 3/4 cup of milk, you need 1.5 cups. But if your only measuring cup is 1/4 cup, you can convert: 1.5 cups = 12 tablespoons, and 12 ÷ (4 tbsp per 1/4 cup) = 3 scoops of 1/4 cup.
Similarly, if a recipe calls for 1 tablespoon but you only have a teaspoon measure, you know that 1 tablespoon = 3 teaspoons, so you use 3 teaspoon scoops.
Original recipe calls for: 2 cups flour, 1/2 cup sugar, 1/3 cup oil, 1 tsp vanilla, 1/2 tsp salt
For water and water-like liquids (milk, juice, thin sauces), volume and weight are nearly equivalent in metric: 1 milliliter of water weighs approximately 1 gram. This makes metric volume-to-weight conversions trivial for liquids:
In US units, 1 cup of water weighs about 237 grams or 8.345 ounces. One fluid ounce of water weighs about 29.57 grams or 1.043 ounces.
| Measurement | Volume | Notes |
|---|---|---|
| 1 dash | ≈ 1/8 tsp (0.6 mL) | Used for bitters and flavorings |
| 1 splash | ≈ 1/2 tsp to 1 tsp | Informal measurement |
| 1 pinch | ≈ 1/16 tsp | What fits between thumb and forefinger |
| 1 jigger (bartending) | 1.5 fl oz (44.36 mL) | Standard cocktail measure |
| 1 pony | 1 fl oz (29.57 mL) | Small cocktail measure |
| 1 wine glass | 4-5 fl oz (118-148 mL) | Varies by glass size |
| 1 coffee cup | 6 fl oz (177 mL) | Standard US coffee cup |
| 1 metric cup | 250 mL | Used in Australia, NZ, Canada |