How to Find Out Square Footage of Someone Else's House

By Fraser Sherman ; Updated April 05, 2017
Couple with real estate broker

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Knowing a home's square footage isn't about idle curiosity, it's a matter of cold, hard cash. If you're buying or selling a home, "comps" – the sale price of comparably sized homes – is a standard tool for measuring a house's worth in the marketplace. Comps also play a role in setting or disputing property tax assessments. Fortunately, you may be able to find the information with just some online research.

Tax Assessment Website

The simplest place to start your research is the property tax assessor's website for your county. Assessments are public records, so they're free to look up online or off. The records include the relevant information assessors use to set property taxes: land value, millage rates (the amount per $1,000 used to calculate taxes on property), acreage, square footage and heated square footage.

Alternative Research

If your county doesn't have property-tax information online, you can research the tax assessor's hard-copy records at the county courthouse. If a lot of homes are for sale in the neighborhood you're looking at, you can also check the ads. Square footage is a basic fact buyers like to know, just like the number of bathrooms. Browse the newspaper and see what you can turn up. Local real estate websites may also provide the information.

Tip

You don't need to survey the entire sales history of your street. Three to five comps will do the trick.

Choosing Comparables

Property tax assessments and sale prices should be based on the current housing market. Sales from three years ago, for instance, won't help you determine a competitive price for your house now. Look for homes that have sold in the past 90 days, though in a sluggish market going further back might be okay. Also make sure the homes are genuinely comparable:

  • Square footage shouldn't be more than 10 percent larger or smaller than the home you own, or want to buy.
  • The comps should have the same number of bathrooms and bedrooms.
  • Comps should be in the same neighborhood and the same school district. If two homes are in different districts, that can make a big difference to the appraised value.
  • Check for special cases. A house that sold low because it's on a toxic waste dump isn't a good comp if yours isn't in the same situation.

Using the Information

If you're satisfied the homes are genuinely comparable to one you want to sell or buy, look at the sale prices. You want yours to be competitive with similar homes – going ultra-high can hurt you, and pricing really low might lose you money. If you're disputing your property tax assessment, you'll need to use your assessor's appeals process. At some point, you'll present the comps as evidence that your tax bill is too high compared to what the neighbors are assessed.