Irregular plot area calculator.
Calculate a trapezoid or four-corner plot area from measured sides or coordinate points, then show square feet and acreage.
Irregular plot area inputs
Calculated from the trapezoid measurements you entered. Ensure corners are entered in boundary order and use a licensed surveyor for legal, construction or title decisions.
Method: A trapezoid uses average parallel-side length × perpendicular height. A four-corner plot uses the shoelace formula to sum signed triangular areas around its boundary.
Inputs used: First parallel side = 50 ft; Second parallel side = 70 ft; Perpendicular height = 100 ft
Assumptions: The result uses the values, units and options shown in the input snapshot.
Scope and warnings: Calculated from the trapezoid measurements you entered. Ensure corners are entered in boundary order and use a licensed surveyor for legal, construction or title decisions. Rounding and excluded real-world terms can make an external result differ.
How this irregular plot area calculator works
A trapezoid uses average parallel-side length × perpendicular height. A four-corner plot uses the shoelace formula to sum signed triangular areas around its boundary.
A worked example
A trapezoid with 50 ft and 70 ft parallel sides and 100 ft perpendicular height has 6,000 sq ft of area.
Can this establish a legal boundary area?
No. Measured field angles, curved boundaries, bearings, encroachments and survey standards require a licensed survey professional.
Calculations run on your device. Review your results before exporting or sharing them.
Enter geometry in boundary order
For a trapezoid, use the two parallel sides and their perpendicular separation. For four coordinates, start at any corner and continue around the boundary without crossing lines.
The result is a measurement screen. Curves, slopes, bearings, irregular boundaries, encroachment and legal area determination require a licensed land survey professional.
Published by ToolMitra — methods and editorial approach.