Contents

Using conversion constants

Converting from Imperial units

Converting from Metric units

Converting from Geographic units

United State Survey Foot

Additional Equivilants


Using conversion constants

The following is a list of conversion constants that can be utilized in converting from one measurement system to another. The measurement system to be converted should be multiplied by the associated conversion constant. For example, to convert feet to centimeters, multiply feet by the conversion constant of 30.48 (27 feet x 30.48 = 822.96 centimeters).

Converting from Imperial units

Multiply

by

to obtain

acres

0.4046856

hectares

acres

43560.0*

square feet

acres

4046.856

square meters

acres

0.0015625*

square miles

acres

4840.0*

square yards

feet

30.48*

centimeters

feet

0.0003048*

kilometers

feet2

0.3048

meters

feet (U.S. survey foot)

0.304800609601**

meters

feet

0.00018939394

miles

feet

304.8*

millimeters

square feet

0.000022956

acres

square feet

929.0304*

square centimeters

square feet

0.09290304*

square meters

square feet

0.00000003587

square miles

inches

2.54*

centimeters

inches

0.0254*

meters

inches

0.000015782

miles

inches

25.4*

millimeters

inches

0.027777778

yards

square inches

6.4516*

square centimeters

square inches

0.00064516*

square meters

square inches

645.16*

square millimeters

miles

160934.4*

centimeters

miles

5280.0*

feet

miles

63360.0*

inches

miles

1.609344*

kilometers

miles

1609.344*

meters

vmiles

1760.0*

yards

miles

1.15077945

nautical miles3

square miles

640.0*

acres

square miles

27878400.0*

square feet

square miles

2.589988110647

square kilometers

yards

914.4*

millimeters

yards

91.44*

centimeters

yards

0.0009144*

kilometers

yards

0.9144*

meters

yards

0.000568182

miles

square yards

0.000206611

acres

square yards

0.83612736*

square meters

square yards

0.0000003228305

square miles

Converting from Metric units

Multiply

by

to obtain

centimeters

0.03280839895

feet

centimeters

0.3937007874

inches

centimeters

0.00001*

kilometers

centimeters

0.01*

meters

centimeters

0.000006213711922

miles

centimeters

10.0*

millimeters

centimeters

0.01093613298

yards

square centimeters

0.001076391042

square feet

square centimeters

0.15500031

square inches

hectares

2.471054073

acres

hectares

107639.1042

square feet

kilometers

1000000.0*

millimeters

kilometers

100000.0*

centimeters

kilometers

1000.0*

meters

kilometers

1093.613298

yards

kilometers

3280.839895

feet

kilometers

39370.07874

inches

kilometers

0.6213711922

miles

square kilometers

247.1054

acres

square kilometers

10763910.42

square feet

square kilometers

0.386102158496

square miles

meters

100.0*

centimeters

meters

3.280839895

feet

meters

3.280833333331

feet (U.S. survey foot)

meters

39.37007874

inches

meters

0.001*

kilometers

meters

0.0006213711922

miles

meters

1000.0*

millimeters

meters

1.093613298

yards

square meters

0.0002471054

acres

square meters

10.76391042

square feet

square meters

0.0000003861003

square miles

millimeters

0.1*

centimeters

millimeters

0.003280839

feet

millimeters

0.03937007874

inches

millimeters

0.000001*

kilometers

millimeters

0.001*

meters

millimeters

0.0000006213711922

miles

millimeters

0.001093613298

yards

square millimeters

0.00001076391042

square feet

Converting from Geographic units

Multiply

by

to obtain

degrees

1.111111111

grads

degrees

0.017453292

radians

grads

0.9*

degrees

grads

0.015707963

radians

radians

57.2958

degrees

radians

63.6620

grads

United State Survey Foot

In 1959, the directors of the National Bureau of Standards and the United States Coast and Geodetic Survey agreed on a redefinition of the inch-centimeter relationship. This redefinition defined 1 inch as equal to 2.54 centimeters, exactly, or 1 foot as equal to 0.3048 meters, exactly. However, their agreement stipulated that the older value for 1 meter equaling 39.37 inches, exactly, be retained for identifying the U.S. survey foot. One of the reasons for this retention was that the State Plane Coordinate Systems, which are derived from the national geodetic control network, are based on the relationship of 1 meter equaling 39.37 inches, exactly. The difference between these two values for the foot is very small, two parts per million, which is hardly measurable but not trivial when computational consistency is desired. Fundamental survey units, such as rods, chains, statute miles, acres, sections, and townships, all depend on the relationship of 1 meter equaling 39.37 inches, exactly. The following list represents the corrected values (or U.S. survey values), using the 39.37-inch conversion value:

Multiply

by

to obtain

acres

0.4046873

hectares

acres

10.0*

square chains

acres

43560.0*

square feet

acres

4046.873

square meters

acres

0.0015625*

square miles

acres

160.0*

square rods

chains

66.0*

feet

chains

100.0*

links

chains

20.11684

meters

chains

0.0125*

miles

chains

4.0*

rods

square chains

0.1*

acres

s

quare chains

0.04046873

hectares

square chains

4356.0*

square feet

square chains

404.6873

square meters

square chains

0.00015625*

square miles

square chains

16.0*

square rods

feet

0.01515152

chains

feet

1.515152

links

feet

0.304800609601**

meters

feet

0.00018939394

miles

feet

0.06060606

rods

square feet

0.00002295684

acres

square feet

0.000009290341

hectares

square feet

0.00000003587006

sections

square feet

0.0002295684

square chains

square feet

0.09290341

square meters

square feet

0.00000003587006

square miles

square feet

0.003673095

square rods

square feet

0.0000000009963907

townships

hectares

2.471044

acres

hectares

24.71044

square chains

hectares

107638.7

square feet

hectares

10000.0*

square meters

hectares

0.003861006

square miles

hectares

395.3670

square rods

links

0.01*

chains

links

0.66*

feet

links

0.2011684

meters

links

0.000125*

miles

links

0.04*

rods

meters

0.04970960

chains

meters

3.280833333331

feet

meters

4.970960

links

meters

0.0006213699

miles

meters

0.1988384

rods

square meters

0.0002471044

acres

square meters

0.0001*

hectares

square meters

0.0000003861006

sections

square meters

0.002471044

square chains

square meters

10.76387

square feet

square meters

0.0000003861006

square miles

square meters

0.03953670

square rods

square meters

0.000000010725

townships

miles

80.0 *

chains

miles

5280.0*

feet

miles

8000.0*

links

miles

1609.347

meters

miles

320.0*

rods

square miles

640.0*

acres

square miles

258.9998

hectares

square miles

1.0*

sections

square miles

6400.0*

square chains

square miles

27878400.0*

square feet

square miles

2589998.0

square meters

square miles

102400.0*

square rods

square miles

0.027777778

townships

rods

0.25*

chains

rods

16.5*

feet

rods

25.0*

links

rods

5.029210

meters

rods

0.003125*

miles

square rods

0.00625*

acres

square rods

0.002529295

hectares

square rods

0.0625*

square chains

square rods

272.25*

square feet

square rods

25.29295

square meters

square rods

0.000009765625*

square miles

sections

27878400.0*

square feet

sections

2589998.0

square meters

sections

1.0*

square miles

sections

0.027777778

townships

townships

36.0*

sections

townships

1003622400.0*

square feet

townships

93239945.0

square meters

townships

36.0*

square miles

Additional Equivilants

   

width of township

6 miles

1 township

36 sections

1 mi2 (usually)

1 section

1 mi2

27,878,400 ft2

mean polar radius of Earth

6373 km or 3960 mi

Earth radius at Pole (Clarke Ellipsoid)

6,356.6 km

Earth radius at Equator (Clarke Ellipsoid)

6,378.2 km

* Constants are exact.

** A coordinate system in U.S. survey feet may be converted to a coordinate system in meters by scaling the system to a scale factor of 0.304800609601. An exact conversion can be accomplished by multiplying U.S. survey feet by the fraction 1200/3937.

1 A coordinate system in meters may be converted to a coordinate system in U.S. survey feet by scaling the system to a scale factor of 3.28083333333. An exact conversion can be accomplished by multiplying meters by the fraction 3937/1200.

2 The foot is one-third of the Imperial standard yard, which is defined to be 0.9144 meters, exactly. Thus the foot is defined as 0.3048 meters, exactly.

3 Represents the international nautical mile and also the U.S. nautical mile. The international nautical mile is defined to be 1852 meters, exactly. However, the U.K. nautical mile is defined to be the average distance on the earthís surface subtended by one minute of latitude, thus being 6080 feet, exactly, or 1853.184 meters, exactly.