Calculations and Conversions

Township = 36 sections, each 1mi²
Section = 640 acres
Quarter section = half a mile square (160 acres)
Eighth section = half a mile long, north and south, and a quarter of a mile wide-80 acres
A sixteenth section = a quarter mile square (40 acres)
The sections are all numbered 1 to 36, commencing at the northeast corner.

An acre contains 4,840 yd², or 43,560 ft². A square acre measures 208.71 ft on each side. 

Land Measure

To find the number of acres in a body of land, multiply the length by the width and divide the product by 160. When the opposite sides are unequal, add them, and take half the sum for the mean length or width. 

Common Measure

Long Measure
12in. = 1ft.
3ft. = 1yd.
5.5yd. = 1rod
320rods = 1mi.
1mi. = 5,280ft.

Square Measure
144in² = 1ft²
9ft² = 1yd²
30.25yd² = 1rod²
160rod² = 1 acre 
4,840yd² = 1 acre
43,560ft² = 1 acre
640 acres = 1mi
An acre is equal to a square whose side is 208.71 ft.

Dry Measure
2pt = 1qt
8qt = 1 peck
4 pecks = 1bu
1bu. contains 231in³ or approximately 1.25ft3.

Liquid Measure
4 gills = 1pt
2pt = 1qt
4qt = 1ga
1ga contains 231in³. 
1ft³. equals 7.5ga. 

Cubic Measure
1728in³ = 1ft³
27ft³ = 1yd³
128ft³ = 1 cord
40ft³ = 1 ton (shipping)
2,150.42in³ = 1 standard bu.
231in³ = 1 U.S. standard ga.
1ft³ = about 4/5 of a bu.

Metric Measurements

Length
1 mm = 0.039in
1 cm = 0.393in
1 m=3.281ft; 1.093yd15 
1 km = 0.621mi
1in = 25.4mm; 2.54cm
1ft = 0.305m; 30.48cm
1yd = 0.914m; 91.4cm
1mi = 1.609km; 1609m

Area
1cm² = 0.155in²
1m² = 10.764ft²; 1.196yd²
1ha = 2.471 acres
1km² = 0.386mi²; 247.11 acres
1in² = 6.45cm²
1ft² = 0.093m²; 929cm²
1yd² = 0.836m²; 8361cm²
1 acre = 0.405 hectare; 4047m²
1mi² = 2.589km²; 258.9 hectares

Mass
1g = 0.035oz
1kg = 2.205lbs
1 metric ton (1000 kg) = 2,205lbs
1oz = 28.35g
1lbs = 0.454kg
1 ton (2,000 lbs) = 0.907 metric ton
1 tonne = 1,000kg
1 tonne = 2,204.6lbs

Velocity
1km/hr = 0.621mi/hr
1mi/hr = 1.609km/hr

Power
1(k W=1.341 horsepower
1 horsepower=0.746 (k W)

Reduce irregularly shaped areas to a combination of rectangles, circles and triangles. Calculate the area of each and add them together to get the total area. 

Example: If b=25’, h=25’, L1=30’, W1=42’, L2=33’, W2=31’, 
then the equation is:

Area= ((b x h) / 2) + (L1 x W1) + (L2 x W2)
=((25 x 25) / 2) + (30 x 42) + (31 x 33)
= 2595 sq. ft.

Another way to calculate area is to draw a line down the middle of the property for length. Measure from side to side at several points along this line. Use the averages of these values as the width. Calculate the area as a rectangle. 

Example: If ab=45’, c=19’, d=22’, e=15’, f=17’, g=21’, h=22’, 

then the equation is:

Area=(ab) x [(c+d+e+f+g+h) / 6]
=(45) x [(19+22+15+17+21+22) / 6]
= 870 sq. ft. 

Formulas For Estimating Wheat Yields

Bushels = 
(Heads per foot) x (spikelets per head) x (2.3) 
(divided by row space in inches) x 0.48 per acre

Bushels Per Acre of Wheat = 
(# heads/3 foot row) x (spikelets/head) x (kernels spikelet) x 0.142 
(divided by row spacing (inches))