ETEnggToolsEngineering utilities
Back to tools

Land Area Calculator

Calculate land or plot area for triangle, quadrilateral, and N-sided irregular plots using boundary side lengths, required diagonals, and Heron's formula.

Calculator

Land area calculator

Boundary sides

Required diagonals

1 needed

Plot sketch

Preview
1234

Calculated area

Square feetWaiting for valid lengths
Square feet-
Square meters-
Gaj / square yards-
Acres-
Cents-
Review geometry

Enter every boundary side length before final area calculation.

Method

The plot is split into triangles from point P1, then each triangle area is calculated with Heron's formula.

Diagonals

An N-sided plot needs N - 3 diagonals for this triangulation method.

Check

Measure diagonals on site or from a survey drawing. Boundary sides alone are not enough for irregular plots.

How to use this tool

Enter the number of plot sides.
Enter each boundary side length in feet, meters, or yards.
Enter the highlighted diagonals required to split the plot into triangles.
Review area in square feet, square meters, gaj, acres, and cents.

Assumptions

The calculator triangulates the plot from point P1.

An N-sided plot uses N - 3 diagonals for this triangulation method.

Each triangle area is calculated using Heron's formula from three measured lengths.

Limitations

Side lengths alone do not uniquely define an irregular plot area.

Entered dimensions must match one consistent triangulation from the same survey points.

For legal property work, verify measurements against the official survey or local land records.

Formula notes

Triangle area = sqrt(s x (s - a) x (s - b) x (s - c)), where s = (a + b + c) / 2.

Total plot area is the sum of all triangle areas.