What Is Square Foot (US Survey)?
A square foot US survey is a way to measure area. It is the area of a square where each side is exactly one US survey foot long. This unit was created for mapping and land measuring in the United States. It is almost the same as the regular square foot that most people use, but it is based on an older, slightly different length of the foot.
Definition
One square foot US survey is the area inside a square with sides of one US survey foot.
In metric terms:
- 1 square foot US survey is about 0.092903414 square meters.
- 1 square meter is about 10.763915 square feet US survey.
The square foot US survey is almost the same size as the international square foot that is based on the normal foot of 0.3048 meter. The difference is so small that it does not matter in daily life, but it can matter in careful land surveying.
History / Origin
The square foot US survey comes from the way land was measured in the United States many years ago.
Long ago, the United States used a foot that was defined from an old rule: 1 foot US survey is exactly 1200 divided by 3937 meters. This value is a little longer than the international foot that the world uses today.
In 1959, several countries agreed to a common standard for the yard and the foot, called the international yard and foot. After this agreement, the regular foot became exactly 0.3048 meter. However, surveyors in the United States kept using the old US survey foot for mapping and land records. Changing it at that time would have made existing maps and property lines slightly shift.
Because the side of the square stayed as the US survey foot, the area based on it became known as the square foot US survey. It kept the old size so that land descriptions in legal documents stayed stable.
In recent years, the United States has moved away from the US survey foot for new survey work, but many older maps and records still use it. That is why this unit still matters for land survey history and for understanding old data.
Symbol & Abbreviation
Common ways to write square foot US survey include:
ft² (US survey)sq ft (US survey)ft^2 (US survey)in plain text
The extra words US survey are important. They tell you that the area is based on the US survey foot, not on the international foot. If you only see ft² or sq ft and nothing else, it usually means the normal international square foot.
Current Use Around the World
The square foot US survey is a special unit. It is not a common everyday unit and it is mainly linked to the United States.
Today it is used in these ways:
- Old land records Many property deeds, land plats, and survey maps in the United States still show area in square feet US survey.
- Surveying and mapping data Some older digital maps and geographic information system files were built with this unit, so surveyors must know it to avoid small errors.
- Legal and historical work Lawyers, land surveyors, and historians may need this unit when reading or comparing old documents.
Outside the United States, this unit is almost never used. Most countries use square meters and hectares for land area. Even inside the United States, new work is now often done in square meters or in the regular international square foot. The square foot US survey mainly survives in older or very precise surveying work.
Example Conversions
Below are some simple conversions between square foot US survey and other units. Values are rounded for easy use.
| Square foot US survey | Square meter | Explanation |
|---|---|---|
| 1 sq ft US survey | about 0.0929034 m² | Area of a small floor tile |
| 10 sq ft US survey | about 0.9290 m² | Area a bit smaller than one square meter |
| 100 sq ft US survey | about 9.2903 m² | Small room or shed |
| 1 000 sq ft US survey | about 92.903 m² | Size of a small apartment |
Here are some conversion facts you can use:
- To get square meters from square feet US survey, multiply by about 0.092903414.
- To get square feet US survey from square meters, multiply by about 10.763915.
Comparing with other familiar units:
- 1 square foot US survey is about 144 square inches US survey.
- 1 square yard US survey is 9 square feet US survey.
- 1 acre US survey is 43 560 square feet US survey.
Related Units
Units closely related to the square foot US survey include:
- Square foot (international) The standard square foot based on the international foot of 0.3048 meter. Very slightly smaller than the square foot US survey.
- Square inch A much smaller area unit. There are 144 square inches in one square foot US survey.
- Square yard A larger unit used for land and floor area. One square yard US survey equals 9 square feet US survey.
- Acre (US survey) A land area unit used for farms and plots. One acre US survey equals 43 560 square feet US survey.
- Square meter The basic metric area unit. It is used all over the world in science, engineering, and daily life.
- Hectare A metric unit for large land areas. One hectare equals 10 000 square meters, which is about 107 639 square feet US survey.
FAQs
What is the difference between a square foot and a square foot US survey?
Both units measure area and are almost the same size. A square foot US survey is based on the older US survey foot, which is very slightly longer than the international foot. This makes the square foot US survey very slightly bigger than the normal square foot, but the difference is tiny and only matters for very precise surveying.
Why was the square foot US survey used?
It was used because land in the United States was measured and recorded using the US survey foot for many years. When the world moved to the international foot, changing old land records would have caused tiny shifts in property lines. To avoid this, surveyors kept using the square foot US survey for those records.
Is the square foot US survey still used today?
New projects in the United States are now mostly done with the international foot or with metric units such as the meter. However, the square foot US survey is still used when working with old maps, deeds, and survey data that were created with that unit.
Do normal home floor plans use square feet US survey?
In everyday life, when people talk about the size of a house or a room in square feet, they almost always mean the international square foot. The difference from the square foot US survey is so small that it does not matter for normal home sizes.
How can I tell if a number is in square feet US survey?
Look for words such as US survey, survey foot, or symbols like ft² US survey next to the number. Land survey reports or government mapping documents may explain which foot they use. If nothing is written, it usually means the normal international square foot, especially in modern documents.
Should students learn this unit in detail?
Most students only need to know the regular square foot and the square meter. The square foot US survey is mainly important for people who work with land surveying, mapping, or old property records. Knowing that it exists, and that it is almost the same as the regular square foot, is usually enough.
Can I safely treat the square foot US survey as the same as the regular square foot?
For school math problems, house plans, and normal life, yes, you can treat them as the same. For professional surveying or legal land work, experts use the exact values and clearly state which foot they mean.