Spike's Calculators

Determine the area in acres, for a circular plot

A = πR² ÷ 43560 (there are 43560 ft² in one acre) where A = area R = radius π = 3.14159

diameter of plot = 66 feet (ft)--R = diameter ÷ 2 66 ÷ 2 = 33 ft for the radius 3.14159 * ( 33*33) ÷ 10000 = A 3.14159 * 1089 = 3421.19151 ÷ 43560 = 0.07853975 acres (ac) or 1 ÷ 0.07853975 = 1 : 12.7 of an acre (ac)

- the diameter of the plot in feet
- select number of digits required for the result

- the area of the plot in square feet
- the plot area in (part of) acres
- fraction of an acre

- Area of a Circle from Diameter in Metres
- Area of a Circle from Foot and Inch Diameter
- Basal Area from Diameter in Centimetres
- Basal Area from Diameter in Inches
- Basal Area from Girth Measured @ Breast Height in Centimetres
- Basal Area from Girth Measured @ Breast Height in Inches
- Circumference (Girth) of a Log from Diameter, Foot and Inch
- Convert Diameter in Centimetres to Girth in Inches
- Circumference (Girth) of a Log from Diameter, Inch and Fraction
- Diameter of Tree from Circumference Measurement
- Diameter/Centimetres to Inches/Quarter Girth
- Fixed Area Plot, Acres
- Fixed Area Plots, Hectares
- Number of Trees and Tree Spacing Calculated from Basal Area
- Square Feet (Quarter Girth) to Square Centimetres
- Square Feet (Quarter Girth) to Square Metres
- Trees per Hectare to Trees per Acre
- Trees per Acre to Trees per Hectare