Square Footage Calculator

A square foot is a unit of area measurement that measures feet and represents the surface area of a two-dimensional plane. Almost all construction projects start with this measure. Flooring, carpeting, tiling, painting, sodding, and mulching are all sold by the area to be covered so knowing what area will be worked on before calculating project cost is essential. This calculator calculates the area of eleven different shapes and converts the result into square yards, meters, inches, acres. It can also estimate material requirements and costs.

What is a square foot?

Area is the size of a two-dimensional surface on a plane occupied by a shape. The area obtained when each side is measured in feet is called square foot, abbreviated as ft2. The word "square" before the unit indicates that it is an area measurement and not a length or volume measure.

If you measure in yards, you get square yards; if you measure in meters, you get square meters. You can calculate the area in one unit and then convert the result to another unit. Since this calculator does the conversion for you, you can directly obtain results in either square meters or acres without having to deal with formulas when entering values in feet.

Basic calculation formula:

The simplest and most common shape is a rectangular or square room. The area is the product of length and width.

Suppose the length of a room is 12 feet and the width is 10 feet. Multiplying these two values results in an area of 120 square feet. If different units were used to measure, such as feet and inches, then you must convert them into the same unit before multiplying.

How to measure a room:

Select the appropriate shape and measure each side as requested by the calculator, entering your values in. Hold the tape straight and measure to the very end of the finished surface. When measuring a room, measure at floor level from wall to wall.

• Select a shape from the menu.

• Measure and enter each dimension. You can switch units in any input field so it's no problem to mix feet and inches.

• First check the area shown at the top and then the other units that are shown in the result.

• In the Materials and Costs section you can add quantities and prices to plan for a buffer.

If the room has an irregular shape such as an L-shape or a room with alcoves, divide it into simpler shapes. Calculate the area of each section and add them together to get the total area. Rectangles and triangles can be combined to represent most real-life rooms.

Convert length units.

Make all your measurements in the unit you prefer and convert them later. Here are the conversion relationships for lengths used in the calculator:

Conversion of area units

Area units are different from length units. Because area is two-dimensional, the conversion factor for length must be multiplied by itself. One square yard is equal to nine square feet, not three square feet. A square foot is equal to 144 square inches.

Area formulas for different shapes

For each shape in the menu standard geometric formulas are used. Below you can find examples where the unit of measure is feet.

For a circle the diameter is used, i.e. the total width through the middle. If you have measured the radius, double it and enter this value. For a church wall that is under an inclined roof or vaulted ceiling, two different heights must be entered as it is a right-angled trapezoid.

Material and cost estimation

Knowing the net area is only half of the job. When actually ordering, you need to plan for additional material to allow for cutting, waste, damage and pattern matching. This extra requirement is known as the wastage. You can add this wastage in the Materials & Costs section.

As a general rule of thumb when laying simple tiles or flooring you should allow for between 5 and 10 percent wastage. For diagonal layouts, complex patterns or many corners in the room you should increase the amount of waste. When you enter the price per square foot, meter or yard the calculator will multiply this by the total area (including waste) to give an estimate cost.

For materials sold in boxes with a coverage area per box listed, divide the total square footage by the coverage area per box to determine how many boxes you need and round up.

Scope of area calculation

Calculating area is used in many different places around a house or garden.

• Flooring, including carpets, tiles, laminate and vinyl floors are sold by the square foot or meter.

• For paint and drywall, wall surface area is used; here, the shape of the walls with windows helps.

• In landscape gardening, lawn areas, seeds, mulching materials, gravel and terraces must be calculated.

• Land and property are measured in square feet and acres.

• The specifications for heating and air conditioning systems are based on the area to be heated or cooled.

This calculator is for planning purposes only. Measure twice to be sure. When ordering actual product, allow a buffer as the coverage and waste will vary by product. Check with your supplier for quantities.