Four milliliters (4 mL) is a unit of volume in the metric system. It is commonly used in scientific and medical contexts to measure liquids. For reference, 4 mL is equivalent to about 0.14 fluid ounces, which is a small amount, roughly the volume of a teaspoon. In everyday use, 4 mL can be found in various applications, such as in medicine for dosing liquid medications or in cooking for measuring small quantities of ingredients. It is also used in laboratories for precise measurements in experiments involving chemicals or biological samples.