How to find commercial property sales comps for free
In this article
Short answer: start with your city or county's public sales data, usually on the assessor or finance department's site. Pull recent sales of similar buildings nearby, confirm each one against the deed, and divide price by square footage. You'll get a solid starting list for free, but no lease details, cap rates or concessions.
This guide uses New York City as the example. Other places publish different fields, but the process is the same.
Where to find free sales data
| Source | What you get | What to double-check |
|---|---|---|
| County or city sales data | Recent sales by date, location and building type | Whether it was a normal market sale |
| Assessor record | Parcel and building details | Whether the square footage is current |
| Recorded deed | Who bought, who sold, and what changed hands | Portfolio deals, where the price may cover several buildings |
| Broker or owner announcement | Occupancy, renovation, deal context | Whether it's the same deal and date |
| Active listing | Competing supply | An asking price isn't a sale price |
Search your county's site for "property sales", "sales download" or "recorded deeds". New York City publishes rolling sales files covering twelve months, with building type and square footage.
How to build your comp list
- Describe your property in a sentence: use, neighborhood, size, condition.
- Pick a search area and time frame, and write them down so someone else could repeat it.
- Filter to the same property type and a similar size.
- Look up each sale and check exactly what was sold.
- Keep a one-line reason for including or dropping each one.
Match what actually drives value. For industrial, that's things like clear height, loading and yard space. For retail, it's frontage and tenants.
Set aside any sale with a zero or unusually low price until you've read the deed. These are often transfers between related parties or sales of a partial interest.
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Match the parcel, not just the street address. In New York City that means borough, block and lot. ACRIS has deeds and other documents for Manhattan, Brooklyn, Queens and the Bronx back to 1966. Outside the city, use your county recorder.
Watch for sales covering several lots or buildings. If you can't split the price reliably, leave that sale out of your per-square-foot numbers and note why.
Don't recognize the buyer? Here's how to trace an LLC to the people behind it.
How to calculate price per square foot
Divide the sale price by the building's square footage, and use the same type of square footage for every comp. Don't mix gross and rentable area without saying so.
Here's a made-up example:
| Comp | Price | Gross square feet | Price per square foot | Decision |
|---|---|---|---|---|
| A | $4,800,000 | 24,000 | $200 | Keep |
| B | $6,600,000 | 30,000 | $220 | Keep |
| C | $9,000,000 | Three buildings, no split | Can't calculate | Drop |
That gives you a rough range of $200 to $220 per square foot. It's a screen, not a valuation, because income, leases and condition still matter.
What free records won't tell you
- Cap rate. You'd need a reliable net operating income figure as well as the price.
- Rent, concessions or remaining lease term.
- The building's condition, or work the buyer had to fund.
For those, ask the broker or owner who was on the deal. For a formal value, hire an appraiser.
If you do this every week, the hours add up. At that point it's worth comparing paid tools. Here are the best CoStar alternatives, several of them with comps.
Frequently asked questions
Can you find commercial comps for free?
Yes, for sale prices. Many counties publish sales data or deeds online for free. Lease comps are harder to find. CompStak's exchange is free for brokers who share their own.
Is LoopNet good for comps?
Not really. LoopNet is a listings site, so it mostly shows asking prices, not closed sales.
How many comps do I need?
There's no fixed number. Three to five genuinely similar sales is more useful than twenty loose ones.
How recent should comps be?
As recent as you can get, ideally within the last 12 months. Go further back only in slow markets, and say so if you do.
