1. Select your shape
Choose from rectangle, circle, triangle, trapezoid, L-shape, annulus, or wall-and-window layouts to match your project.
What is uneven sides square footage?
Uneven sides square footage is the area of a shape where the sides are different lengths, measured in square feet. For triangular areas with three uneven sides, use Heron's formula: Area = sqrt[s(s-a)(s-b)(s-c)], where s = (a+b+c)/2. For four-sided shapes with uneven sides, split into two triangles and add their areas.
Getting started
How to Calculate Square Footage with Uneven Sides
To calculate square footage of an area with uneven sides, first determine the shape. For triangles, measure all three sides and use Heron's formula. For four-sided shapes, divide into two triangles by measuring a diagonal, then calculate each triangle and add the results.
2. Enter your measurements
Input dimensions in feet, inches, yards, meters, or centimeters. The Square Foot Calculator converts units automatically.
3. Get area and cost
View results in square feet, square yards, square meters, and acres. Add a material price per unit to estimate total project cost.
Quick reference
Reference
1 acre = 43,560 square feet
1 square yard = 9 square feet
1 square meter = 10.764 square feet
1 square inch = 0.00064516 square feet
Material pricing
Calculate Cost of Materials
Enter the price per square foot of material to estimate total cost. The calculator accepts pricing in square feet, square inches, square yards, or square meters and converts to the correct total based on your area.
There are 2 steps to calculate material cost:
- Enter the price per unit area. For tiling projects, enter the price per box and the number of square feet each box covers. For carpet, enter the cost per square yard. For flooring installation with hardwood or laminate, enter the cost per square foot.
- Select the unit of area that matches your pricing. The Square Foot Calculator multiplies your total area by the unit price to produce an estimated material cost, including labor costs when added to the per-unit price.
To calculate the volume of bulk materials like mulch or gravel for landscaping, convert area to cubic yards or cubic meters by multiplying the area by the depth of material.
Core formula
Basic Formula for Area
Area is the amount of space occupied by a 2-dimensional shape. The shape could be a floor, a wall, a playground, or a field. The simplest formula for area applies to any rectangular shape:
Area = Length × Width
Measure the length and width of the space in feet. Multiply the two values to get the area in square feet. A rectangular room that is 12 feet (3.66 meters) long and 10 feet (3.05 meters) wide has an area of 120 sq ft (11.15 sq m).
Square yardage is area measured in yards, and square meters is area measured in meters. Measure in feet, find the area in square feet, then convert to the unit you need.
For an L-shape room, split the floor into 2 rectangular sections, calculate each area, and add the results. Convert all measurements to the same unit before multiplying, if your dimensions are in different units like inches and feet.
Basic Length Conversion
Convert other units of measure to feet with these 4 formulas:
| From | To Feet | Formula |
|---|---|---|
| Inches | Feet | Divide by 12 |
| Yards | Feet | Multiply by 3 |
| Meters | Feet | Multiply by 3.28084 |
| Centimeters | Feet | Divide by 30.48 |
For example, 48 inches ÷ 12 = 4 feet. A measurement of 5 meters × 3.28084 = 16.40 feet. The Square Foot Calculator handles these conversions automatically when you select the input unit.
Unit conversion
Area Conversion
Measure your space in inches or centimeters, calculate area in square inches or square centimeters, then convert to any unit you need, including square feet, square yards, square meters, or acres.
| Unit | Square Feet Equivalent |
|---|---|
| 1 sq ft | 144 sq in |
| 1 sq yd | 9 sq ft |
| 1 sq m | 10.764 sq ft |
| 1 acre | 43,560 sq ft |
A 300 sq ft room equals 33.33 sq yd, 27.87 sq m, or 43,200 sq in. The Square Footage Calculator displays all conversions at once so you can compare units for flooring, carpet, or tiling projects without manual math.
Shape formulas
Area Formulas for Different Shapes
The Square Foot Calculator supports 11 shape formulas for construction, interior design, landscaping, and flooring projects. Each formula below includes a diagram with labeled dimensions.
Triangle Shape
Calculate square foot of a triangle
Using measurements in feet: Area = √[s(s − a)(s − b)(s − c)], where s = (a + b + c) ÷ 2. This is Heron's formula. The 3 sides of the triangle do not need to be the same length. Enter the length of each side in feet and the Square Foot Calculator returns the area in square feet, square yards, and square meters. Use this for corner plots, angled architectural sections, and triangular installation zones.
Trapezoid Shape
Calculate square foot of a trapezoid
Using measurements in feet: Area (ft²) = [(a + b) ÷ 2] × h. The variables a and b are the 2 parallel sides, and h is the perpendicular height between the parallel sides. A trapezoid with parallel sides of 8 feet (2.44 meters) and 14 feet (4.27 meters), with a height of 6 feet (1.83 meters), has an area of 66 sq ft (6.13 sq m).
Waste factor
Adding 10% Surplus for Materials
Add a 10% surplus to your calculated area to account for material waste during cutting, breakage, and pattern matching. This waste factor applies to flooring, carpet, tiling projects, and landscaping materials.
Original Area
100 sq ft
+10%
Order Amount
110 sq ft
Total Material = Area × 1.10
A room with 200 sq ft of floor area needs 220 sq ft of material: 200 × 1.10 = 220 sq ft. Increase the surplus to 15% (multiply by 1.15) for diagonal flooring installation patterns or complex tiling projects with many cuts. The Square Foot Calculator includes a waste factor field for this calculation.
FAQ
Frequently Asked Questions
How do I calculate square footage with uneven sides?
For a triangle with three known sides, use Heron's formula: s = (a+b+c)/2, then Area = sqrt[s(s-a)(s-b)(s-c)]. For four-sided areas, split into two triangles using a diagonal measurement.
How do I find the area of a lot with 4 uneven sides?
Measure a diagonal across the lot to create two triangles. Calculate each triangle area using Heron's formula (measure all three sides of each triangle), then add the two areas together.
What is Heron's formula?
Heron's formula calculates triangle area from three side lengths: First find s = (a+b+c)/2, then Area = sqrt[s(s-a)(s-b)(s-c)]. No angle measurement needed.
How many square feet is a triangle with sides 10, 12, and 14 feet?
A triangle with sides 10, 12, and 14 feet has an area of approximately 58.79 square feet. Using Heron's formula: s = 18, Area = sqrt[18 x 8 x 6 x 4] = sqrt[3456] = 58.79 sq ft.
Can I calculate a trapezoid with uneven non-parallel sides?
Yes, if you know the two parallel sides and the height between them, use: Area = [(a + b) / 2] x height. The non-parallel sides do not affect the area calculation.
How accurate is the uneven sides method?
Heron's formula gives exact results when side measurements are accurate. Measure each side carefully with a tape measure. Small measurement errors compound in the square root calculation.