Title: Metrication in the United States
Content:   Metrication (or metrification) is the process of introducing the International System of Units, also known as SI units or the metric system, to replace a jurisdiction's traditional measuring units. Although U.S. customary units have been defined in terms of metric units since the 19th century, as of 2021 the United States is one of only three countries (the others being Myanmar and Liberia) that have not officially adopted the metric system as the primary means of weights and measures. The United States has official legislation for metrication; however, conversion was not mandatory and many industries chose not to convert, and unlike other countries, there is no governmental or major social desire to implement further metrication. Although customary units are used more often than metric units in the U.S., the SI system is used extensively in some fields such as science, medicine, electronics, the military, automobile production and repair, and international affairs. Post-1994 federal law also mandates most packaged consumer goods be labeled in both customary and metric units.
Title: Metrication in the United States
Content:  In science, metric use is essentially universal, though additional specialized units are often used for specific purposes in various disciplines (such as the parsec and light year in astronomy), consistent with worldwide use. Laboratories in the United States almost exclusively use the metric system and SI, such as the Celsius and Kelvin scales for temperature. Earth sciences, such as hydrology and geology, continue to use customary units for field surveying, due both to the legacy of many decades of data collection and to the need to work with the construction industry, which has not adopted the metric system. American irrigation engineers, for example, talk in acre-feet and cubic feet per second, whereas most other irrigation engineers would refer to gigalitres and cubic metres per 
Title: Unit of measurement
Content:  Metric systems of units have evolved since the adoption of the original metric system in France in 1791. The current international standard metric system is the International System of Units (abbreviated to SI). An important feature of modern systems is standardization. Each unit has a universally recognized size. Both the imperial units and US customary units derive from earlier English units. Imperial units were mostly used in the British Commonwealth and the former British Empire. US customary units are still the main system of measurement used in the United States outside of science, medicine, many sectors of industry, and some of government and military, and despite Congress having legally authorised metric measure on 28 July 1866. Some steps towards US metrication have been made, particularly the redefinition of basic US and imperial units to derive exactly from SI units. Since the international yard and pound agreement of 1959 the US and imperial inch is now defined as exactly 0.025 m, and the US and imperial avoirdupois pound is now defined as exactly 453.592 g.
Title: System of measurement
Content:  Metrication is complete or nearly complete in almost all countries. US customary units are heavily used in the United States and to some degree in Liberia. Traditional Burmese units of measurement are used in Burma. U.S. units are used in limited contexts in Canada due to the large volume of trade; there is also considerable use of Imperial weights and measures, despite de jure Canadian conversion to metric. A number of other jurisdictions have laws mandating or permitting other systems of measurement in some or all contexts, such as the United Kingdom – whose road signage legislation, for instance, only allows distance signs displaying imperial units (miles or yards) – or Hong Kong. In the United States, metric units are used almost universally in science, widely in the military, and partially in industry, but customary units predominate in household use. At retail stores, the liter is a commonly used unit for volume, especially on bottles of beverages, and milligrams, rather than grains, are used for medications. Some other standard non-SI units are still in international use, such as nautical miles and knots in aviation and shipping.
Title: Imperial and US customary measurement systems
Content:  In the 1960s a metrication program was initiated in most English-speaking countries, resulting in either the partial or total displacement of the imperial system or the US customary system of measure in those countries. The current status of imperial and US customary units, as summarised by NIST, is that "the SI metric system is now the official system of units in the United Kingdom, while the customary units are still predominantly used in the United States". The situation is however not as clear-cut as this. In the United States, for example, the metric system is the predominant system of measure in certain fields such as automobile manufacture even though 
Title: Metric system
Content:  of deteriorating platinum-iridium. The range of decimal prefixes has been extended to those for 1024 (yotta–) and 10−24 (yocto–). The International System of Units has been adopted as the official system of weights and measures by all nations in the world except for Myanmar, Liberia, and the United States. In the United States, the Metric Conversion Act of 1975 declared the metric system to be the “preferred system of weights and measures” but did not suspend use of customary units, and the United States is the only industrialised country where commercial and standards activities do not predominantly use the metric system.
Title: United States customary units
Content:  of 1893 and, in practice, for many years before. These definitions were refined by the international yard and pound agreement of 1959. Americans use customary units in commercial activities, as well as for personal and social use. In science, medicine, many sectors of industry, and some government and military areas, metric units are used. The International System of Units (SI), the modern form of the metric system, is preferred for many uses by the U.S. National Institute of Standards and Technology (NIST). For newer units of measure where there is no traditional customary unit, international units are used, sometimes mixed with customary units; for example, electrical resistance of wire expressed in ohms (SI) per thousand feet.
Title: System of measurement
Content:  Both imperial units and US customary units derive from earlier English units. Imperial units were mostly used in the former British Empire and the British Commonwealth, but in all these countries they have been largely supplanted by the metric system. They are still used for some applications in the United Kingdom but have been mostly replaced by the metric system in commercial, scientific, and industrial applications. US customary units, however, are still the main system of measurement in the United States. While some steps towards metrication have been made (mainly in the late 1960s and early 1970s), the customary units have a strong hold due to the vast 
Title: Metrication
Content:   Over time, the metric system has influenced the United States through international trade and standardisation. The use of the metric system was made legal as a system of measurement in 1866 and the United States was a founding member of the International Bureau of Weights and Measures in 1875. The system was officially adopted by the federal government in 1975 for use in the military and government agencies, and as preferred system for trade and commerce. Attempts in the 1990s to make it mandatory for federal and state road signage to use metric units failed and it remains voluntary. A 1992 amendment to the Fair Packaging and Labeling Act (FPLA), which took effect in 1994, required labels on federally regulated "consumer commodities" to include both metric and US customary units. As of 2013, all but one US state (New York) have passed laws permitting metric-only labels for the products they regulate. After many years of informal or optional metrication, the American public and much of the private business and industry still use US customary units today. At least two states, Kentucky and California, have even moved towards demetrication of highway construction projects.
Title: US Metric Association
Content:  The US Metric Association (USMA) advocates the completion of the ongoing US conversion to the metric system, officially known as the International System of Units (SI). In support of this mission, the USMA provides a public medium for information and discussion, reports of metrication within the US, a history of the use of metric units in the US, a related bibliography including relevant laws, an answer source for industrial inquiries, a cadre of people knowledgeable about the metric system, training aids and supplies for educators and the public, a certification program that has been used in industry, and various citations and awards for those supporting this mission. The USMA is in cooperative communication with various state and federal governments, both legislative and executive, and various industrial and professional societies, such as the Institute of Electrical and Electronics Engineers (IEEE), many of whom are involved in standards development.

Question: what kind of metric system does the us use?
Answer: international units.
United States customary units.