When it comes to cooking and baking, measuring ingredients precisely is extremely important for achieving the desired results. Two of the most common units used to measure liquid ingredients are cups and milliliters (mL). However, there is often confusion over the exact conversion between 1 cup and mL. So is 1 cup equivalent to 200 mL or 250 mL?
The Definition of a Cup
First, it is important to understand exactly what a “cup” is. A cup is a standardized cooking measure used in the United States and some other countries. 1 cup is defined as exactly 236.588 mL. So a cup is not exactly equal to 250 mL or 200 mL.
Here are some key facts about measuring cups:
- 1 US customary cup = exactly 236.588 mL
- Cups used for cooking in the US are usually metal or plastic cups with volume markings on the side indicating 1 cup, 1/2 cup, 1/3 cup, etc.
- A US cup has a volume of 8 fluid ounces or 16 US tablespoonfuls.
- In the UK, 1 imperial cup is equivalent to 284 mL while in Canada 1 Canadian cup = 227 mL.
- When a recipe simply lists “1 cup” it is referring to the US customary cup of 236.588 mL.
So the US customary cup is a standardized unit of volume defined to be exactly 236.588 mL – not 250 mL or 200 mL.
Cups vs. Milliliters in Recipes
Understanding that a US cup is 236.588 mL, it is easy to see that 1 cup does not equal exactly 250 mL or 200 mL. However, when converting between cups and milliliters in recipes, the slight differences may not make a major impact:
- 1 US cup = 236.588 mL
- 250 mL = approximately 1.058 US cup
- 200 mL = approximately 0.85 US cup
So 250 mL is slightly more than 1 US cup while 200 mL is slightly less. When actually measuring ingredients, these small variations likely won’t make a big difference or ruin your recipe.
For example, if a recipe calls for “1 cup of milk” you can measure out 236.588 mL with a liquid measuring cup or approximate with a 250 mL milliliter measuring cup. The 13.412 mL difference between 236.588 mL and 250 mL is only about 1 tablespoon and won’t significantly alter the recipe.
Similarly, for a recipe requiring 200 mL of liquid, using a 0.85 US cup measure would be essentially the same. The differences are small enough that your recipe will generally turn out fine.
When Precision Matters
There are some instances when precision is more important when measuring between cups and milliliters:
- Large batch or commercial cooking/baking – When scaling up a recipe to feed large groups or produce big batches, small measurement variations get multiplied so precision matters more.
- Baking – Baked goods often rely on very precise measurements and right proportions of ingredients, so every mL can make a difference.
- Scientific experiments – Laboratory experiments require exact measurements down to the mL so conversions must be precise.
In these cases, it’s crucial to know that 1 US customary cup = 236.588 mL and to measure as precisely as possible based on the exact conversion.
Typical Conversions Between Cups and Milliliters
Here is a table summarizing some common conversions between US customary cups and milliliters:
| US Cups | Milliliters |
|---|---|
| 1 cup | 236.588 mL |
| 3/4 cup | 177.441 mL |
| 2/3 cup | 157.725 mL |
| 1/2 cup | 118.294 mL |
| 1/3 cup | 78.863 mL |
| 1/4 cup | 59.147 mL |
| 1 tablespoon | 14.787 mL |
| 1 teaspoon | 4.928 mL |
This table can provide a helpful guide for measuring common liquid volumes either in cups or milliliters. Keep in mind cups should always be US customary cups.
Metric Cups vs. US Customary Cups
The cups and milliliter volumes discussed so far apply to the US customary system. In the metric system, there is also a unit referred to as a “metric cup” which equals 250 mL. So a metric cup is different from a US customary cup.
Here is a summary comparing metric cups to US cups:
- Metric cup = 250 mL exactly
- US customary cup = 236.588 mL exactly
- 1 metric cup = approximately 1.058 US cups
- 1 US cup = approximately 0.946 metric cups
So if a recipe from a non-US country calls for “cups” it likely means metric cups of 250 mL. Be careful not to confuse metric cups with the smaller US customary cups of 236.588 mL.
Summary
In summary:
- The US customary cup is defined as exactly 236.588 mL
- So 1 US cup does not equal exactly 250 mL or 200 mL
- However, for simplicity 250 mL can be approximately considered 1 cup and 200 mL close to 0.85 cups in everyday cooking
- When precision matters, always convert based on 1 cup = 236.588 mL exactly
- Metric cups of 250 mL are different from the smaller US customary cups of 236.588 mL
Knowing the difference between cups and milliliters is important for accurate cooking and baking. Consult a conversion table and measure carefully for the most precise results.
