Plot Area Calculator (3-Sided / Triangular)
Calculate the exact area of a triangular plot from three side lengths using Heron's formula. Marla, Kanal, Acre.
Construction
Plot Area Calculator (3-Sided / Triangular)
Generated on April 29, 2026
Plot Shape (3 sides — cyclic polygon, max-area assumption)
Plot Pricing — convert any rate to all others
?What is the Plot Area Calculator (3-Sided / Triangular)?
A 3-sided (triangular) plot area calculator computes the exact area of a triangular piece of land from its three side lengths using Heron's formula. Triangular plots are surprisingly common in Pakistan and South Asia — corner plots where two roads meet at a non-90° angle, irregular pie-shape lots at roundabouts, fragmentary plots left after road widening, agricultural fields bounded by canals or natural features, and inheritance subdivisions where a larger plot is split diagonally between heirs. Unlike four-sided plots (which need an averaging or cyclic-quadrilateral approximation), three side lengths uniquely determine a triangle's shape and area — this calculator gives a mathematically exact result, not an estimate.
The Formula
Heron's formula is one of the few cases in surveying geometry where you can get a mathematically exact area from side lengths alone — three sides uniquely determine a triangle (up to mirror reflection, which doesn't affect area). The semi-perimeter s is half the sum of the three sides; the formula then computes the area as the square root of s times the differences (s − a), (s − b), (s − c). The result is exact to within the precision of your input measurements. This is why land registries worldwide accept triangular subdivisions with just three side measurements, while four-sided plots typically require additional information (a diagonal or angle) for legal precision.
Common Triangular Plot Reference Areas
Sample triangle dimensions converted to standard Pakistani area units (272 sq ft Marla).
| Sides (ft) | Sq ft | Marla | Kanal | Acre |
|---|---|---|---|---|
| 30 × 40 × 50 | 600 | 2.21 | 0.110 | 0.0138 |
| 50 × 50 × 50 (equilateral) | 1,083 | 3.98 | 0.199 | 0.0249 |
| 60 × 80 × 100 | 2,400 | 8.82 | 0.441 | 0.0551 |
| 75 × 75 × 90 | 2,941 | 10.81 | 0.541 | 0.0675 |
| 100 × 100 × 100 | 4,330 | 15.92 | 0.796 | 0.0994 |
| 120 × 90 × 145 | 5,395 | 19.83 | 0.992 | 0.1239 |
| 200 × 250 × 300 | 24,748 | 91.0 | 4.55 | 0.568 |
Put It in Perspective
A 3-Marla triangular plot fits a small 2-bedroom single-story home with creative angled-wall design.
A 10-Marla triangular plot at a corner is prime real estate for a retail showroom or café with great visibility from two streets.
Roadside fragments under 1 Marla are typically too small to build on but useful for kiosks or parking.
Triangular agricultural parcels are often the result of canal or road realignment — common in Punjab's irrigated belt.
Practical Examples
A triangular corner plot with sides 60, 80, 100 ft is 2,400 sq ft (a 3-4-5 right triangle scaled up) — about 8.82 Marla in the standard 272 sq ft system.
An equilateral plot with each side 50 ft has area ≈ 1,083 sq ft ≈ 3.98 Marla — the smallest typical urban subdivision.
A roadside fragment of 30, 40, 50 ft has area 600 sq ft ≈ 2.21 Marla — a common shop plot remainder after road widening.
A pie-shape lot at a roundabout (120 × 90 × 145 ft) has area ≈ 5,395 sq ft ≈ 19.83 Marla ≈ 0.99 Kanal.
Agricultural triangle 200 × 250 × 300 ft = 24,748 sq ft ≈ 91.0 Marla ≈ 0.568 acres — typical mid-size farm parcel.
An isosceles plot 75 × 75 × 90 ft = 2,941 sq ft ≈ 10.81 Marla — typical 11-Marla irregular plot.
Frequently Asked Questions
Popular Conversions
Jump to a ready-made conversion — useful for quick reference and sharing: