What Is Yard (US Survey)?
The yard US survey is a unit for measuring length. It was mainly used in land surveying in the United States. It is very close to the normal yard, but not exactly the same. It is based on the old US survey foot and is mostly kept today for reading and working with older maps and records.
Definition
A yard US survey is defined as exactly 3 US survey feet.
One US survey foot is defined as exactly 1200 divided by 3937 of a meter. This makes the yard US survey equal to:
- 3 US survey feet
- 36 US survey inches
- Exactly 3600 divided by 3937 meters
In decimal form this is about:
- 1 yard US survey ≈ 0.9144018288 meters
The normal international yard, which most people use today, is exactly 0.9144 meters. So the yard US survey is only a tiny bit longer than the normal yard.
History / Origin
In the 1800s scientists wanted to connect old units like the foot and yard to the newer metric system. In 1893, the United States made a rule called the Mendenhall Order. It said that the yard US survey and foot US survey would be based on the meter using exact fractions.
Later, in 1959, the United States and other English speaking countries agreed to use a new standard called the international yard. It was set at exactly 0.9144 meters. After this change, the yard US survey and foot US survey stayed mainly for land surveying, so that large map systems would not have to be fully changed at once.
Over time, the difference between the survey units and the international units caused small mismatches in big mapping and engineering projects. Because of this, the United States decided to stop using the US survey foot as a separate standard. New projects are now expected to use the international foot and yard, or use meters directly.
Symbol & Abbreviation
The usual symbol for the yard US survey is:
- yd for yard
Sometimes, to make it clear that it is the survey version, people write:
- yd (US survey)
- yd US sur
These longer labels help to show that it is not the normal international yard, even though the basic symbol is the same.
Current Use Around the World
Today, the yard US survey is a very special use unit. It is not used in everyday life.
United States
- Mostly appears in land surveying records, especially older ones
- Used in some state plane coordinate systems for mapping land and property lines
- Found in old engineering plans, highway drawings, and legal land documents
Outside the United States
- Almost never used in daily measurement
- Sometimes seen in international mapping work that must match old US data
New projects are slowly moving away from the yard US survey and US survey foot. Most new work uses the international yard and foot, or just uses meters.
Example Conversions
Below are some simple conversions to help you feel how long a yard US survey is.
To Meters
- 1 yard US survey ≈ 0.9144018 m
- 10 yards US survey ≈ 9.144018 m
- 100 yards US survey ≈ 91.44018 m
To US Survey Feet and Inches
- 1 yard US survey = 3 US survey feet
- 1 yard US survey = 36 US survey inches
- 5 yards US survey = 15 US survey feet
- 20 yards US survey = 60 US survey feet
To Miles (Survey)
In survey work, 1 mile is usually taken as 5280 feet US survey.
- 1 mile (US survey) = 1760 yards US survey
- 880 yards US survey = 0.5 mile (US survey)
Comparing to the International Yard
The difference is very small but real for precise work.
- 1 yard US survey ≈ 1.00000044 international yards
- 1000 yards US survey are only about 0.44 millimeters longer than 1000 international yards
For normal daily measuring this change does not matter. For huge maps and long distance surveys it does matter, which is why experts pay attention to it.
Related Units
- US Survey Foot the base unit from which the yard US survey is built, 3 of these make one survey yard
- International Foot the modern standard foot, slightly different from the US survey foot
- International Yard the common yard used today, exactly 0.9144 meters
- Mile (US Survey) a larger survey unit, equal to 5280 US survey feet or 1760 US survey yards
- Meter the main metric unit of length used worldwide in science and engineering
FAQs
Is the yard US survey the same as the yard on a ruler?
Not exactly. The yard on most rulers today is the international yard. The yard US survey is only a tiny bit longer, but the difference matters in very accurate surveying.
Why did surveyors use a special yard?
Surveyors used a special yard and foot because they were defined using an exact fraction of the meter in 1893. This kept old measurements consistent when maps covered very large areas.
Do I need to worry about the yard US survey in daily life?
No. For shopping, sports, and school projects, the normal yard or meter is fine. The yard US survey mostly matters for people who work with old land records or detailed maps.
Which is more accurate, the survey yard or the international yard?
Both are very accurate definitions. The international yard is now the official standard for general use. The survey yard is kept mainly so old surveying work still lines up correctly.
How can I tell if a map uses survey yards or international yards?
Look in the map legend or notes. They often say “US survey feet” or “US survey yards” if those units are used. If it does not say, modern maps usually use the international units or meters.
Are survey units going to disappear?
They are slowly being phased out for new work. However, they will still appear in old documents, so people who work with historic or legal land data will need to understand them for many years.