Land area calculator
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.
Use this land area calculator to estimate irregular plot area from boundary side lengths and the diagonals needed to split the plot into triangles. It is useful for quick plot checks when the shape is not a simple rectangle and the result needs to be reviewed in square feet, square meters, gaj, acres, cents, and related units.
Common engineering uses
- Triangle, quadrilateral, pentagon, and N-sided plot checks when side lengths and diagonals are known.
- Irregular land area calculations based on a clear triangulation instead of only side lengths.
- Early comparison of plot measurements before checking official survey drawings or local land records.
Outputs to review
- Area in square feet, square meters, gaj, acres, cents, and other practical land units.
- A side-count driven sketch that highlights which diagonals are needed for the selected polygon.
- Triangle-by-triangle area breakdown using Heron's formula.
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.
How to use the result
Enter the number of plot sides, then enter each boundary side length and the highlighted diagonals from the same survey points. The calculator triangulates from one reference point and sums the triangle areas. Side lengths alone do not uniquely define an irregular polygon, so diagonals or coordinates are necessary for a reliable area estimate. Keep a sketch of point names with the entered dimensions so the calculated triangles match the actual plot instead of a different possible shape.
Assumptions, limitations, and formulas
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.
Common questions
Can I calculate irregular plot area from side lengths only?
Usually no. Side lengths alone do not uniquely define an irregular plot shape. The calculator asks for the diagonals needed to split the plot into triangles so the area can be calculated from a defined geometry.
What is gaj in land measurement?
Gaj is commonly treated as one square yard, equal to 9 square feet. Local land records may still use traditional units differently, so verify official property work against the relevant local records.
Is this suitable for legal property measurement?
No. It is a practical checking tool for entered dimensions. Legal, sale, registration, and construction decisions should be verified against official survey drawings, revenue records, or a qualified surveyor.