Insulation

HomeDepot.com – This online insulation calculator from home improvement superstore Home Depot makes it easy to determine how much insulation your addition is going to require. Simply input the height and length of the walls, the length and width of attic or crawlspace areas and the number of windows and doors (and their heights and widths). Then choose your state on the site’s zone map and click “calculate” to get your custom results.

EnergyEfficientSolutions.com – This calculator is for calculating spray foam requirements only. The calculator needs to know the total area to be insulated and the desired cure thickness. The site does provide a chart to refer to for thickness recommendations based on different applications.

Drywall

CSGNetwork.com – With this online drywall calculator, you simply add in the height and perimeter of the room, the length and width of the ceiling and the dimensions for any sloped walls or excluded areas. Then pick the size of drywall sheets from those listed to learn how many sheets of drywall you’re going to need and how much it is going to cost.

Paint

BenjaminMoore.com – With this paint calculator from Benjamin Moore, you can quickly and easily find out exactly how much paint your new addition will require. Measurements can be input in either English or Metric and will require the length, width and height of the room’s walls as well as any doors or windows. The calculation results are based on two coats of paint and do not include the ceiling.

Wallpaper

WallPaperWholesaler.com – This site helps you calculate how many single rolls of wallpaper you need to wallpaper the walls of your addition. You have two options to choose from – entire room or individual wall calculations. For entire room results, simply input the width, length and height of the room and click “calculate now.” For individual walls, input the height and width of the walls you want to wallpaper and click “calculate now.”

MyHomeIdeas.com – This wallpaper calculator provides only entire room calculations, but it may prove to be more accurate as it does take into account the room’s windows and doors. You will have to add the lengths and heights of all the walls, rounding up to the nearest foot instead of inputting individual wall dimensions. For windows and doors, round up to the nearest inch when inputting the total measurements for each.

Estimates Only

There are literally hundreds of online home addition calculators available on the Internet, but searching for them can take a lot of your time and energy. The ones listed here are of the highest quality and offer exceptional value and accurate information. It is important to note, however, that these calculators provide only an estimate of the job or material costs as prices and labor rates do fluctuate rapidly in the building industry. It is not recommended to rely solely on these tools as a means of determining a precise estimate but rather a ballpark figure for what you can expect to pay for the job you’re doing.