Square Footage Calculator

Calculate room area for multiple shapes, estimate flooring costs with waste, and figure out how much paint you need — all in one tool.

📐 Calculate Room Area

🪵 Estimate Flooring Cost

Total Area (sq ft)

Cost per sq ft ($)

Waste % (recommended 10%)

🛒 Shop flooring materials from trusted retailers

Home Depot Flooring → Lowe's Flooring →

🎨 Estimate Paint Needed

Room Length (ft)

Room Width (ft)

Ceiling Height (ft)

Number of Coats

Number of Doors

Number of Windows

Price per Gallon ($)

🛒 Shop paint from trusted retailers

Home Depot Paint → Lowe's Paint →

How to Calculate Square Footage

Square footage measures the area of a two-dimensional space. It's essential for home improvement projects like flooring, painting, tiling, and landscaping.

Common Room Shapes

Rectangle: Length × Width
Triangle: ½ × Base × Height
Circle: π × Radius²
L-Shape: Split into two rectangles and add their areas

Flooring Cost Tips

Always add 10–15% extra for waste when purchasing flooring materials. Diagonal patterns and complex layouts require more waste allowance. Hardwood typically costs $3–$8 per sq ft, laminate $1–$5, and tile $1–$15 depending on material.

Paint Coverage Guide

One gallon of paint covers about 350 sq ft of smooth wall surface. Textured walls may reduce coverage to 300 sq ft per gallon. Standard doors are about 21 sq ft and windows about 15 sq ft — subtract these from your wall area for a more accurate estimate.

Try our mortgage calculator for home buying estimates
Use the percentage calculator for quick math

Frequently Asked Questions

How do I calculate square footage of a room?

Multiply the length by the width in feet. For example, a 12×10 foot room is 120 square feet. For irregular shapes, break the room into rectangles and add them together.

How much flooring do I need with waste factored in?

Add 10% waste for standard installations and up to 15% for diagonal or patterned layouts. Multiply your total square footage by 1.10 or 1.15 to get the amount to purchase.

How many gallons of paint do I need for a room?

One gallon of paint covers approximately 350 square feet. Calculate total wall area (perimeter × height), subtract doors and windows, then divide by 350.

How do I convert square feet to square meters?

Divide square feet by 10.764 to get square meters. For example, 500 sq ft ÷ 10.764 = 46.45 m².

What shapes can I calculate area for?

This calculator supports rectangles, triangles, circles, and L-shapes. Each shape has its own input fields for the relevant dimensions.

How do I measure an L-shaped room?

Break the L-shape into two rectangles. Measure length and width of each section, calculate their areas separately, then add them together.

Should I round up when buying materials?

Yes, always round up. Materials are sold in whole units, and having a small surplus is better than running short mid-project.

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