A 1,400 square foot home, priced against three nearby sales that average $650.44 a square foot, comes out at about $910,617. This home value calculator turns comparable sales into an estimate and a range you can defend.
How do agents value a home from comparable sales?
They start from recent sales of similar homes. Divide each sale price by its size to get a price per square foot, average the results, and multiply by the size of your home. The tool follows those same steps, then lets you nudge the answer up or down for condition or location. The table shows the three default comparables.
| Comparable | Price | Size | Price per sq ft |
|---|---|---|---|
| Sale 1 | $880,000 | 1,350 sq ft | $651.85 |
| Sale 2 | $925,000 | 1,450 sq ft | $637.93 |
| Sale 3 | $860,000 | 1,300 sq ft | $661.54 |
| Average | $650.44 |
What does the adjustment do?
With no adjustment, $650.44 times 1,400 square feet gives $910,617, and a range of 5% either way runs from $865,086 to $956,147. Say your kitchen is older than the ones in those three sales. Enter minus 4% and the estimate becomes $874,192, with a range of $830,482 to $917,902.
The number of sales matters as well. Drop the third and two are left, the average moves to $644.89 and the estimate to $902,848. That’s why the calculator warns you when you enter fewer than three comparables: one odd sale can drag the result a long way.
Price per square foot is a blunt tool, and it works best when the sales are close in size. A 1,300 square foot home and a 1,450 square foot home in the table sit within 12% of each other, and their rates are similar at $661.54 and $637.93. A much bigger or smaller sale often carries a different rate, so leave it out.
What if one sale doesn’t fit?
Say Sale 2 was a rushed estate sale and you’d rather not count it. Keep only Sale 1 and Sale 3, and the average per square foot is $656.70. Times 1,400 square feet, that’s $919,373, about $8,756 above the three sale figure. A single sale moved the answer by under 1%, which is fine here, but the same swap with a wild outlier could move it by tens of thousands. That’s the reason to look at each sale before you trust the average.
What can throw the estimate off?
Pick recent sales, in the same area, with a similar home. Three months is a common rule of thumb, though a slow market may force you to look further back. Mix a detached house with a condo, or a busy street with a quiet one, and the average gets distorted. Size isn’t the only driver of price, and you can’t squeeze the rest into one number without some loss: lot size, age, layout, parking and views all count, yet the single adjustment box has to stand in for every one of them.
Don’t mistake this for an appraisal. A lender orders its own valuation, and a listing price can differ from what a home sells for. Not sure of your own home’s area? Measuring a few rooms takes minutes, and a wrong size throws off every dollar of the result. The square footage calculator will settle it.
The sources behind this page
None of it is market data. The three sales, the size and the range are sample inputs, so replace them with real sold prices from your area. The site has no link to any listing service, appraiser or government body. A few bucks spent on a proper appraisal can save a lot of guessing. Use the output as one input. Then set it next to a proper appraisal and the asking prices you see in person, because you’ll trust it more that way.
Want to see how a value has moved over the years you’ve owned? The home appreciation calculator does that. Planning to sell? The home sale proceeds calculator shows what’s left after costs, and the mortgage affordability calculator shows what a buyer could borrow.
About this calculator
- What it does
- Estimate the value of a home from comparable sales and price per square foot, with an adjustment and a range.
- Category
- Real Estate
- Last checked
- September 30, 2026
- Result type
- Estimate for information only, not tax advice.
Frequently asked questions
How many comparable sales should I use?
At least three. The calculator warns you when you enter fewer, because one unusual sale can skew the average.
How recent should the sales be?
Choose sales from the last three months, in the same area, for a similar home.
What does the adjustment do?
It raises or lowers the estimate by a percentage. Use a negative number when your home is in worse shape than the comparables.
Is this the same as an appraisal?
No, it's an estimate built from your inputs. A lender or appraiser will set their own value.
What is the range for?
It shows a low and a high value around the estimate. The default is 5%, which gives $865,086 to $956,147.
Sources and updates
Updated: . How we check rates · Editorial team · Updates