How do I calculate the area of a plot with 4 different sides?

Use the quadrilateral area calculator above. Enter all 4 side lengths (A-B, B-C, C-D, D-A) and at least one diagonal. The tool applies Heron's formula to both triangles formed by the diagonal, then sums them for the total area. Results appear instantly in sq ft, sq m, acres and more.

Can I calculate the area of an irregular plot without angles?

Yes. Enter all 4 side lengths and one diagonal measurement (which you can measure physically across the plot). The calculator uses Heron's formula and does not require any angle measurements.

What is the formula for area of a quadrilateral with 4 different sides?

Split the quadrilateral into two triangles using a diagonal. For each triangle, calculate the semi-perimeter s = (a + b + c) / 2, then area = √(s × (s−a) × (s−b) × (s−c)). Add both triangle areas for the total quadrilateral area.

How do I calculate plot area in square feet?

Select 'Feet' as your input unit, enter your side lengths in feet, and the calculator automatically outputs the result in square feet (ft²) alongside sq meters, acres, cents and other units.

How to calculate the area of land with 4 unequal sides?

Measure all 4 boundary sides and one diagonal of the land plot. Enter these 5 values into the Quadrilateral Area Calculator. The tool computes the area using Heron's formula for both triangles and gives results in multiple units instantly.

What units does the calculator support?

Input units: Meters, Feet, Yards, Centimeters, Inches, Kilometers, Miles, Cent. Output units: Square Meters (m²), Square Feet (ft²), Square Yards (yd²), Acres, Cents, Hectares, Bigha, Katha, Gaj, Guntha.

What is the difference between a regular and irregular plot?

A regular plot has all sides and angles equal (like a square). An irregular plot has sides of different lengths and/or unequal angles (like most real-world land parcels). Use the 4-side calculator or diagonal method for irregular plots.

Can I calculate area for a 5 or 6 sided plot?

Yes. Use the Polygon Area Calculator section and set the number of sides to 5, 6 or up to 10. It uses the Shoelace theorem (Gauss's formula) for polygons with 5+ sides.

Land Area Calculator India – Acre, Bigha, Guntha, Square Feet

Land Area Calculator India – Acre, Bigha, Guntha, Square Feet, Square Meter/h2>
For plots where opposite sides are equal (regular rectangle). Enter length × width.

Simple 4-Side Area Calculator

Enter two adjacent side lengths. Works for square, rectangle, and any plot where you know the length and width (parallel sides). Formula: Area = Length × Width.

Length (Side A to B)

Width (Side B to C)

Irregular Quadrilateral Area Calculator (4 Unequal Sides)

For plots with 4 different side lengths — no angles needed, just one diagonal measurement.

Area Calculator for Land with 4 Different Sides

This is the most popular calculator for irregular plots, agricultural land, and real-world property boundaries. Enter all 4 boundary measurements and one diagonal. Uses Heron's Formula — no angle measurements required.

📐 How to measure the diagonal: Stretch a tape measure diagonally across your plot from corner A to corner C (or B to D). This is the only extra measurement you need.

Side A–B

Side B–C

Side C–D

Side D–A

Diagonal A–C (required)

Triangle, Pentagon & Polygon Area Calculator (3–10 Sides)

For triangular plots, 5-sided, 6-sided or any irregular polygonal land parcel.

Irregular Polygon / Triangle Area Calculator

Select the number of sides (3 to 10), choose your unit, and enter each side length. Uses Heron's formula for triangles, Bretschneider's formula for quadrilaterals, and the Shoelace theorem for 5+ sided polygons.

Number of Sides

Unit

Area Unit Converter

Convert between square feet, square meters, acres, Bigha, Gaj, Guntha and more. Type in any box.

Area Converter – All Units

Square Feet (ft²)

Square Meters (m²)

Square Yards (yd²)

Acres

Cents

Hectares

Ares

Bigha (avg)

Katha (avg)

Gaj

Guntha

Square Inches

Length Unit Converter

Centimeters

Inches

Feet

Meters

Yards

Kilometers

Miles

How to Calculate Plot Area – Complete Guide

Step-by-step instructions for every plot shape, including irregular land with 4 unequal sides.

How to Calculate the Area of a Plot with 4 Different Sides

Most real-world land parcels are not perfect rectangles — they have 4 sides with different lengths. The standard length × width formula does not apply here. Instead, you need to split the quadrilateral into two triangles using a diagonal, then calculate the area of each triangle using Heron's Formula.

Step-by-Step Method

Measure all 4 boundary sides

Using a measuring tape, record the length of each boundary: A–B, B–C, C–D, and D–A. Note the unit (feet or meters).

Measure one diagonal

Stretch your tape diagonally from corner A to corner C (or B to D). This splits the quadrilateral into two triangles.

Calculate area of Triangle 1 (A–B–C)

Use sides AB, BC, and diagonal AC. Apply Heron's formula: s = (AB+BC+AC)/2, then Area₁ = √(s × (s−AB) × (s−BC) × (s−AC))

Calculate area of Triangle 2 (A–C–D)

Use sides AC (diagonal), CD, and DA. Apply Heron's formula again: s = (AC+CD+DA)/2, then Area₂ = √(s × (s−AC) × (s−CD) × (s−DA))

Add the two areas

Total Area = Area₁ + Area₂. The calculator above does this automatically and shows results in sq ft, sq m, acres, cents and Indian units.

Heron's Formula

s = (a + b + c) / 2
Area = √( s × (s−a) × (s−b) × (s−c) )

Total Quadrilateral Area = Triangle₁ + Triangle₂

Calculate Plot Area in Square Feet vs Square Meters

The most common units for plot measurement are square feet (ft²) in India, USA, and the UK, and square meters (m²) in Europe and much of Asia. To convert: 1 square meter = 10.764 square feet.

Our calculator accepts input in feet or meters and instantly shows results in both, along with acres, cents, Bigha, Katha, Gaj, and Guntha — the units most commonly used in India, Bangladesh, and Nepal.

Why "Length × Width" Doesn't Work for Irregular Plots

The simple rectangle formula Area = Length × Width only applies when both pairs of opposite sides are equal and all angles are 90°. For an irregular quadrilateral (where all 4 sides are different), this formula gives incorrect results. Use the diagonal method (Heron's formula) described above for accurate calculations.

How to Measure Land Area with 4 Unequal Sides — Without Visiting the Site

If you have official survey documents (FMB sketch, registry document, or a patta), you can read the 4 boundary dimensions directly and take the diagonal from the sketch. Enter these into the calculator above to instantly get the area in any unit.

Area Calculation for Common Plot Shapes

Shape	Formula	Calculator to Use
Square / Rectangle	Length × Width	Simple 4-Side Calculator ↑
Irregular Quadrilateral (4 unequal sides)	Heron's formula (2 triangles)	Diagonal Calculator ↑
Triangle	√(s(s−a)(s−b)(s−c))	Polygon Calculator (3 sides) ↑
Trapezoid	½ × (a+b) × h	Polygon Calculator ↑
Pentagon / Hexagon	Shoelace Theorem	Polygon Calculator (5–6 sides) ↑
L-shaped / Cross plot	Split into rectangles	Add results from Simple Calculator

Supported Area Units – Global & Indian Land Measurement

Different countries and regions use different units for land measurement. Our calculator supports them all:

Unit	Abbreviation	= Square Meters
Square Foot	ft²	0.0929 m²
Square Meter	m²	1 m²
Square Yard	yd²	0.836 m²
Acre	ac	4046.86 m²
Hectare	ha	10,000 m²
Are	a	100 m²

Unit	Region	≈ Sq Feet
Cent	Tamil Nadu, Kerala	435.6 ft²
Gaj / Gaz	North India	9 ft²
Bigha (avg)	UP, MP, Rajasthan	~14,400 ft² (varies)
Katha	Bihar, West Bengal	720 ft² (varies)
Guntha	Maharashtra, Karnataka	1,089 ft²
Biswa	North India	~1,350 ft² (varies)

Frequently Asked Questions

Common questions about plot area calculation, formulas and land measurement.

Measure all 4 sides and one diagonal of the plot. Use the Diagonal Calculator above — it applies Heron's formula to both triangles formed by the diagonal and gives you the total area in square feet, square meters, acres, and more. No angle measurements are needed.

Split the quadrilateral using a diagonal into two triangles. For each triangle: s = (a + b + c) / 2, Area = √(s(s−a)(s−b)(s−c)). Total area = Triangle 1 + Triangle 2. This works for any irregular quadrilateral regardless of angles.

Yes. You only need the 4 side lengths and one diagonal. Heron's formula does not require angles. This is why it's ideal for physical land measurement — you can measure all values with just a tape measure.

Select "Feet" in the unit dropdown, enter your side measurements in feet, and click Calculate. The result automatically appears in square feet (ft²) at the top of the results, along with conversions to square meters, acres, cents and more.

1 Gaj (also written Gaz) = 9 square feet. So if your plot is 1000 square feet, it is approximately 111 Gaj. Use our Area Converter above to instantly convert between Gaj, square feet, and all other units.

The calculator uses precise mathematical formulas (Heron's formula, Bretschneider's formula, and the Shoelace theorem). Accuracy depends on the precision of your input measurements. For legally binding land registration, always verify with a licensed surveyor.

Yes. FMB (Field Measurement Book) sketches in Tamil Nadu show all boundary dimensions. Read the 4 sides and diagonal from the sketch and enter them into the Diagonal Calculator above to get the area in cents, sq ft, sq m, or any other unit.

For a 5-sided polygon, use the Polygon Calculator above and set "Number of Sides" to 5. For L-shaped plots, divide the L-shape into two rectangles, calculate each separately using the Simple Calculator, and add the results together.

Related Calculators & Tools

More tools on Fictos for land measurement, geometry and conversions.

Land Area Calculator India – Acre, Bigha, Guntha, Square Feet, Square Meter/h2> For plots where opposite sides are equal (regular rectangle). Enter length × width.