1. Select your shape
Choose from rectangle, circle, triangle, trapezoid, L-shape, annulus, or wall-and-window layouts to match your project.
What is wall square footage?
Wall square footage is the surface area of a wall measured in square feet. To calculate wall square footage, multiply the wall height by the wall width, then subtract the area of any windows and doors. Wall square footage is essential for estimating paint, wallpaper, siding, and paneling materials.
Getting started
How to Calculate Wall Square Footage
To calculate wall square footage: multiply wall height by wall width for total wall area, then subtract window and door areas. A wall 12 feet wide and 8 feet tall has 96 square feet. Subtract a 3x4 foot window (12 sq ft) to get 84 square feet of paintable surface.
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.
Calculating Square Footage for Walls
Measure the wall width and the wall height in feet. Multiply the width by the height to get the total wall area in square feet. Subtract the area of any doors or windows to find the exact paint coverage required. A wall that is 12 feet wide and 8 feet tall has a total area of 96 sq ft. A 3 ft × 4 ft window removes 12 sq ft, leaving 84 sq ft of paintable surface.
To subtract multiple windows of the same size from one wall, multiply the window width by the number of windows. Enter the total as the window width in the Square Foot Calculator. Height remains the height of one window.
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 of a wall?
Multiply wall height by wall width for total area, then subtract windows and doors. A 12x8 wall with a 3x4 window = 96 - 12 = 84 square feet of paintable area.
How much paint do I need for a wall?
One gallon of paint covers approximately 350-400 square feet. Calculate the wall square footage minus windows and doors, then divide by 350 for the number of gallons needed per coat.
How do I subtract multiple windows from wall area?
Calculate the area of each window and subtract from the total wall area. For identical windows, multiply one window's area by the number of windows.
Should I subtract doors from wall square footage?
Yes, subtract door areas when calculating paint or wallpaper needs. A standard door is about 3x7 feet (21 sq ft).
How do I calculate square footage for all walls in a room?
Calculate each wall separately and add the areas together. For a rectangular room, measure the two different wall lengths and multiply each by the ceiling height.
How many square feet of wallpaper do I need?
Calculate total wall area minus windows and doors, then add 10-15% for pattern matching waste. Wallpaper is typically sold in rolls covering 28-30 usable square feet.