A common mistake people make when estimating square footage is including non-livable spaces, like garages, patios, or unfinished basements, in the total. In real estate, square footage typically refers to the living area-the finished, heated, and accessible spaces inside the home, like bedrooms, bathrooms, and main living areas. One practical tip I suggest is using a measuring tape or laser measure to take individual room measurements, focusing only on finished, usable spaces. Measure the length and width of each livable room, multiply those numbers to get the square footage of each room, and then add them up to get the total. This approach keeps you focused on the actual living area, which is what most buyers care about. Also, remember that certain spaces, like attics or basements, only count if they're fully finished and accessible by a permanent staircase. Being mindful of these details helps avoid overestimating and ensures you're presenting accurate, helpful information to buyers.
I think the mistake that most people make when estimating square footage is not considering the "per-unit" size or area of the installed item. For example, if you are installing a large-format tile (let's say 24x48) for a bathroom shower surround, the emphasis for measuring square footage should shift towards measuring the number of units needed to fill the space required (essentially you are taking the measurements of the space and counting how many units will be required to fill the space). A transition happens when you start dealing with larger items that some people who are new to the space don't consider, but is a very important consideration to ensure that you aren't needlessly running out of material.