Calculator workspace

Triangle Area Calculator
— Free Square Footage Tool

Enter the base and height of a triangle to calculate its area in square feet instantly.

RECTANGLE DIMENSIONS
Material Waste Factor optional
%
Estimate Material Cost optional
ft²
Results
Square Feet
Square Inches
Square Yards
Square Meters
Acres

Use the Triangle Square Foot Calculator to find the area of any triangular space in square feet. Enter the base and height measurements, and get results in square feet, square yards, square meters, and acres. Perfect for measuring triangular lots, gable walls, corner areas, and architectural features.

Explore Our Square Footage Calculators

Choose a specialized calculator for your exact project — rooms, shapes, materials, outdoor areas, and unit conversions.

What is triangle square footage?

Triangle square footage is the area of a triangular shape measured in square feet. To calculate triangle square footage, multiply the base by the height and divide by 2: Area = 1/2 x Base x Height. Triangle area calculations are used for gable walls, corner lots, angled landscaping features, and decorative architectural sections.

1 ft² = 144 in² 1 ft 1 ft (12 in)

Getting started

How to Calculate Triangle Square Footage

The formula for triangle area is: Area = 1/2 x Base x Height. The base is the bottom side of the triangle. The height is the perpendicular distance from the base to the opposite point. A triangle with a 10-foot base and 6-foot height has an area of 30 square feet.

1. Select your shape

Choose from rectangle, circle, triangle, trapezoid, L-shape, annulus, or wall-and-window layouts to match your project.

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.

20 ft 15 ft 300 ft² Area: 300 ft² Order: 330 ft² +10% waste factor included

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
Area: 300 ft² × Price: $2.80 / sq ft Total: $840.00 estimated material cost

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:

  1. 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.
  2. 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.

Length Width L × W Area = L × W Example: 12 ft × 10 ft = 120 ft²

Basic Length Conversion

Convert other units of measure to feet with these 4 formulas:

From To Feet Formula
InchesFeetDivide by 12
YardsFeetMultiply by 3
MetersFeetMultiply by 3.28084
CentimetersFeetDivide 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 ft144 sq in
1 sq yd9 sq ft
1 sq m10.764 sq ft
1 acre43,560 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

a b c Area = √[s(s−a)(s−b)(s−c)], s = (a+b+c)÷2

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.

Triangle Shape

Calculate square foot of a triangle using base and height

Height Base Area = ½ × Base × Height

Using measurements in feet: Area (ft²) = ½ × Base × Height. This formula is simpler than Heron's formula and works when you know the base and the perpendicular height of the triangle. A triangle with a 10-foot (3.05-meter) base and 6-foot (1.83-meter) height has an area of 30 sq ft (2.79 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 the square footage of a triangle?

Multiply the base by the height and divide by 2. Area = 1/2 x Base x Height. A triangle with a 12-foot base and 8-foot height has an area of 48 square feet.

What is the formula for triangle area?

Area = 1/2 x Base x Height. The height must be perpendicular to the base. For triangles where you know all three sides, use Heron's formula instead.

How do I find the height of a triangle?

The height is the perpendicular distance from the base to the opposite vertex. Measure straight up from the base at a 90-degree angle to the highest point.

What is Heron's formula?

Heron's formula calculates triangle area using three side lengths: Area = sqrt[s(s-a)(s-b)(s-c)], where s = (a+b+c)/2. Use this when you know all three sides but not the height.

How many square feet is a triangle with base 20 and height 10?

A triangle with base 20 ft and height 10 ft is 100 square feet (1/2 x 20 x 10 = 100 sq ft).

Can I use this for gable wall calculations?

Yes, gable walls are triangular. Measure the width of the wall (base) and the height from the wall top to the roof peak. The Triangle Square Foot Calculator gives you the gable area.

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