Convert Imperial fluid ounce to US Fluid ounce (imp fl oz to US Fluid ounce)

Imperial fluid ounce (imp fl oz) and US Fluid ounce (US Fluid ounce) are both units of volume. With the conversion form below, you can effortlessly and accurately convert imperial fluid ounce to us fluid ounce. This free online calculator tool makes it simple and easy to perform the conversion from imp fl oz unit to the US Fluid ounce unit.

Volume is the measurement of the three-dimensional space occupied by a substance, object, or container. The SI derived unit of volume is the cubic meter (m³), while the liter (L)—defined as exactly 1 cubic decimeter (1 dm³ = 0.001 m³)—is the most widely used metric unit for measuring liquids. The milliliter (mL) is equal to exactly 1 cubic centimeter (1 cm³) and is commonly used for beverages, medicines, laboratory samples, and food products.

Different countries and industries use different volume units depending on local standards and applications. In addition to metric units such as the liter, milliliter, and cubic meter, the US and Imperial systems use units including the fluid ounce (fl oz), cup, pint, quart, and gallon. Since the US gallon (3.785411784 L) and the Imperial gallon (4.54609 L) are different units, accurate conversion is essential for cooking, engineering, manufacturing, scientific research, trade, and international product labeling. Learn more in our complete guide to Volume.

About Imperial Fluid Ounce

The Imperial fluid ounce (Imp fl oz) is a unit of volume used in the Imperial measurement system. It is equal to approximately 28.4131 milliliters and is slightly smaller than the US fluid ounce. This unit is commonly found in beverage labeling, cooking recipes, and traditional measurements in the United Kingdom and related regions.

US Fluid Ounce (symbol: US fl oz) is a unit of liquid volume used primarily in the United States. It is part of the US customary measurement system and is commonly used to measure beverages, cooking ingredients, medicines, cosmetics, and packaged consumer products.

The US fluid ounce is defined as 1/128 of a US liquid gallon, making it equivalent to 29.5735295625 milliliters. It differs from the Imperial fluid ounce used in the United Kingdom, which equals approximately 28.4130625 milliliters. Because these units are not interchangeable, accurate conversions are essential for international trade, recipes, product labeling, and scientific applications. This converter follows the official US customary definition, where 128 US fluid ounces = 1 US liquid gallon = 3.785411784 liters. Reference: NIST Guide to the SI – Units Outside the SI.