Triangle Area Calculator — Free Square Footage Tool

Q: 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.

Q: 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.

Q: 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.

What is triangle square footage?

Triangle square footage equals one-half times base times height. Multiply (base × height) ÷ 2 in feet. A triangle with a 12 ft (3.66 m) base and 8 ft (2.44 m) height has 48 sq ft (4.46 m²). For four-sided spaces, use the rectangle calculator or trapezoid calculator.

Getting started

How to Calculate Triangle Square Footage

To calculate triangle square footage, measure the base and the perpendicular height in feet, then apply (base × height) ÷ 2. For triangles with 3 known sides, use Heron's formula instead.

1. Measure base and height

Measure the base and the perpendicular height in feet. Height is measured straight from base to opposite point.

2. Apply ½ × base × height

Triangle area = (base × height) ÷ 2. A 12 × 8 ft triangle has 48 sq ft.

3. Use for triangular spaces

Apply triangle area to gable walls, roof faces, and corner garden beds.

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

Triangle area times price per unit equals material cost. Use triangle square footage for gable walls, peaked roofs, and triangular garden beds.

There are 2 steps to calculate material cost:

Enter the price per square foot of paint, siding, sod, or other material covering the triangle.
The Square Foot Calculator multiplies triangle area by your price for material total.

Triangular surfaces have angled cuts. Add 10-15% extra material for siding, paint, or roofing on triangular shapes.

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.

REFERENCES

Triangle Area Calculator
— Free Square Footage Tool

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