The U.S. government, to avoid confusion, has declared that a foot is slightly shorter than 12 inches, the New York Times reported. This is due to a decision of the National Geodetic Survey (NGS), a sub-branch of the National Oceanic and Atmospheric Administration (NOAA). The NGS defines, maintains and provides access to the National Spatial Reference System (NSRS), which provides a consistent coordinate system that defines latitude, longitude, height, scale, gravity and orientation throughout the United States and its territories.

For years, the precise definition of a foot was split between the U.S. survey foot, which is exactly 12 inches, and the international foot, which is fractionally smaller. Which foot is used varies from state to state, with some mandating the U.S. measurement, some mandating the international measurement, and others having no requirement to use one or the other. The difference is extremely small, making up just 1/100th of a foot per every mile, which has no bearing on most everyday situations but can have an outsize impact when measuring long distances, as surveyors do.

Professionals in the NGS, according to the Times, have spent years correcting errors that come from using the wrong foot in the wrong situation, and so they believed that it would be best if the country formally adopted the international foot as its main standard. A survey of the National Society of Professional Surveyors found that the majority of members agreed, though there remains a vocal minority in favor of the U.S. foot.

The international foot came from global standard setters determining that a foot was 0.3048 of a meter, which is where the slight difference came from. While the United States formally adopted this international foot in 1959, it still allowed individual surveyors to use the old 1893 U.S. foot, creating the division that has bedeviled professionals.

The Times said that the National Institute of Standards and Technology, which sets weights and measures for the country, will give the U.S. foot until 2023 before formally declaring it obsolete.