Real Estate Comps: How to Pull Comparable Sales for Any Address (Free Tools)

Key Takeaways

• Real estate comps are recently sold homes similar to yours in location, size, and condition — they form the basis of every home valuation, from agent CMAs to iBuyer offers.
• The strongest comps sold within the last 90 days, sit within 1 mile of your home in urban areas (or 5 miles in rural markets), and share the same property type.
• Free tools like Zillow, Redfin, Realtor.com, and county recorder websites let you pull sold-home data for any address without an agent.
• Algorithmic home-value estimates carry median error rates of 2–7% for on-market homes and higher for off-market properties.
• Adjusting comps for differences in square footage, condition, and lot size is what separates a rough guess from an accurate price — appraisers and iBuyers both make these adjustments before reaching a final number.

What Are Real Estate Comps?

Real estate comps — short for comparable sales — are recently sold homes that share key characteristics with your property: location, size, condition, and age. Every home valuation method relies on comps. When an agent prepares a comparative market analysis, the foundation is comps. When a bank orders an appraisal, the appraiser pulls comps. When an iBuyer like Opendoor generates a Cash Offer, the pricing model starts with comps in your ZIP code.

The logic is straightforward: a buyer will pay roughly what other buyers have paid for similar homes nearby. Your job is to find the right "similar homes" and adjust for the differences.

Understanding why comps matter when you sell gives you a pricing advantage whether you list with an agent, sell by owner, or request a Cash Offer. This guide covers exactly how to find comps in your area, which free tools to use, how to adjust raw numbers, and how Opendoor's pricing model puts comps to work.

How to Find Real Estate Comps in Your Area (Step-by-Step)

You can pull comps for any address without a real estate license or a paid subscription. Start with a free online portal, filter for the right sales, and cross-check against public records.

Filter for sold (not active or pending) listings first

Active listings show asking prices — not what buyers are paying. Sold listings show confirmed transaction prices, which is the data you need. On Zillow, Redfin, or Realtor.com, toggle the search filter to "Recently Sold" before doing anything else.

Set the date range to 90 days. In a slow market where homes sit longer, extend to 6 months — but recognize that older comps reflect outdated buyer sentiment. Bankrate notes that appraisers follow the same rule: 6 months is the outer limit, and 90 days delivers the most accurate picture.

Match property type, beds, baths, and square footage

A three-bedroom ranch is not comparable to a four-bedroom colonial, even if both sit on the same street. Filter for:

• Same property type — single-family, condo, or townhome (Zillow, 2025)
• Bedroom and bathroom count — within one bed/bath of your home
• Square footage — within 10–20% of your home's finished living area
• Lot size — within 20% for single-family homes where lot premiums exist

A comp two blocks away that matches your floor plan is more reliable than a comp across town that happens to share the same price point.

When to use pending sales as leading indicators

Pending sales — homes under contract but not yet closed — signal where the market is heading. HomeLight reports that pending sales are stronger indicators than closed sales in fast-moving markets because they reflect current buyer behavior, not last month's. Use them as a directional check: if pending prices are climbing above your closed comps, the market is appreciating and your home's value is following.

Track why pending home sales fall through so you know which pending comps to weight more heavily — a sale that fell through on financing says less about value than one that closed smoothly.

Free Tools to Pull Comps for Any Address

You do not need an agent to pull comps. Five free sources cover the data you need — each with strengths and blind spots worth understanding.

Zillow — strongest for breadth, weakest on accuracy for unique homes

Zillow's sold-listing database covers most MLS markets nationwide. The Zestimate — Zillow's algorithmic value estimate — carries a nationwide median error rate of 2.4% for on-market homes and 7.49% for off-market homes. That gap widens for homes with features the algorithm cannot see: a finished basement, a new roof, or a lot backing onto a highway versus a quiet cul-de-sac.

Use Zillow's sold listings as raw comp data. Treat the Zestimate as a starting reference, not a price.

Redfin — tightest accuracy for on-market homes

Redfin's estimate carries a median error rate of 2.07% for on-market homes, the tightest among free algorithmic tools. Redfin also displays days-on-market history and price-change timelines, which help you spot whether a comp sold quickly (strong demand) or lingered (possible overpricing).

The limitation: Redfin pulls from MLS data. Off-market sales and FSBO transactions are missing, which can lead to undervaluation in neighborhoods where private sales are common.

Realtor.com and county recorder offices

Realtor.com rounds out the MLS-based trio with neighborhood-level data and school ratings. County recorder websites fill a different gap: they record every deed transfer, including off-market and FSBO sales that MLS tools miss. The trade-off is a bare-bones interface — no photos, no condition notes — so pair county records with a drive-by to assess the comp's condition yourself.

Opendoor's home value estimator

Opendoor's free home value estimator provides a starting estimate for your address and connects you directly to a Cash Offer request. The estimator draws on comparable sales in your ZIP code and adjusts for your home's specific features — because the estimate feeds into Opendoor's pricing model, it reflects the same data the offer team uses.

What Makes a Good Comp (and How Many You Need)

A strong comp matches your home on five criteria. The more criteria it shares, the more weight it carries in your pricing analysis. Aim for 3–6 comps to triangulate a reliable range — fewer than three leaves too much room for outliers, and more than six starts pulling in less-relevant properties.

Recency — 90 days ideal, 6 months maximum in slow markets

Comps lose relevance as markets shift. A home that sold 4 months ago in a market appreciating at 5% per year already reflects a price that is ~1.7% below current conditions. In fast-moving markets — check the best time to sell a house for seasonal patterns — stick to 90-day comps. Extend to 6 months only when your local market does not produce enough 90-day sales of similar homes (Bankrate, 2025).

Distance — 1 mile urban, 5 miles rural

In urban and suburban areas, search within a 1-mile radius of your home. In rural areas with fewer transactions, expand to 5 miles. Stay within the same school district and neighborhood boundaries when possible — school-district lines affect values even across the same street.

Size, property type, and bedroom count

Match your home's property type exactly: single-family to single-family, condo to condo, townhome to townhome. Keep square footage within 10–20% of your home's finished area, and match bedroom count within one. A 1,500-square-foot home compared against a 2,800-square-foot home will distort your per-square-foot calculations — even after adjustments.

How to Adjust Comps for Square Footage, Condition, and Age

Raw comp prices are a starting point, not a final answer. The homes you find will differ from yours in size, condition, age, or features. Adjustments bridge those gaps.

Price-per-square-foot method

Divide each comp's sale price by its finished square footage to get a price-per-square-foot figure. Average the results across your 3–6 comps, then multiply by your home's square footage for a baseline estimate.

Example: Three comps sell at $200/sqft, $210/sqft, and $195/sqft. The average is $202/sqft. Your 1,800-square-foot home has a baseline value of $363,600.

One note: bigger homes have lower per-square-foot pricing because kitchens and bathrooms — the most expensive rooms per square foot — represent a smaller share of total living area. If your comps are all 20% larger than your home, your per-square-foot figure will run slightly low.

Condition adjustments (renovations, deferred maintenance)

A comp with a renovated kitchen and updated bathrooms sold for more than its raw square footage explains. Bankrate reports that a renovated kitchen adds $15,000–$50,000 depending on market. If your comp has a new kitchen and your home does not, subtract that premium from the comp's price before using it.

The same principle works in reverse: if your home has a new roof and the comp does not, your home carries additional value the raw comp price does not reflect. Agents and appraisers make these adjustments line by line in a CMA — you can approximate by researching renovation costs and returns for your specific upgrades.

Time adjustments for appreciating or declining markets

If your best comps sold 4–6 months ago, adjust for market movement. Track the monthly appreciation or depreciation rate in your ZIP code using Zillow's or Redfin's home value index, then apply it to the comp's sale date.

Example: A comp sold 5 months ago for $400,000 in a market appreciating at 0.4% per month. Time-adjusted value: $400,000 × 1.02 = $408,000. This adjustment becomes essential during seasonal shifts — check the best month to sell a house for market-timing context.

Hyperlocal micro-markets — when averages mislead

Neighborhood-wide averages can mask block-by-block variation. A home backing onto a highway carries a different valuation than one on a quiet cul-de-sac, even in the same subdivision. Flood zones, proximity to schools, and HOA status create micro-markets within the same ZIP code.

When your comps come from different micro-markets, weight the ones closest to your specific location more heavily. A comp one street over is more reliable than a comp a mile away — even if the distant comp matches your square footage more precisely.

Comps vs. Appraisals: What's the Difference?

Comps are raw data. An appraisal is a licensed professional's opinion of value that uses comps plus a physical inspection of the property. Sellers pull comps to set a list price; appraisals happen after a buyer's offer is accepted, ordered by the buyer's lender before funding the mortgage.

A CMA from an agent uses 3–6 comps with manual adjustments for condition, location, and features — similar to what an appraiser does, but without the licensing requirement. The appraiser's report carries legal weight: if the appraisal comes in below the agreed sale price, the buyer's lender will not fund the gap without renegotiation.

Understanding this distinction matters because your comp research and an appraiser's comp research will not always align. Appraisers follow standardized guidelines (6-month maximum recency, 1-mile urban radius), while your DIY comp search can weigh factors the appraiser's form does not capture — like who pays the agent commission in your market and how that affects net proceeds.

How Opendoor Uses Comps to Calculate Your Offer

Opendoor analyzes recent comparable sales in your ZIP code and adjusts for your home's specific features, condition, and local market trends. The result is a Cash Offer you see within 24 hours of requesting it — because the offer is generated from data (not dependent on a single appraiser's availability or a buyer's financing), the timeline compresses from weeks to hours.

Here is how it works:

• You enter your address. Opendoor pulls comparable sales data for your area.
• The model adjusts. Square footage, age, condition, lot size, and recent market trends all factor into the calculation — because Opendoor buys and resells homes at volume across 50+ markets, the model trains on thousands of transactions, not a handful of local comps.
• You receive a Cash Offer. The number reflects what Opendoor will pay, including its 5% service fee disclosed upfront. No hidden costs at closing — because Opendoor profits from volume and speed, the fee structure stays flat.
• You choose your close date. Close in as few as 14 days or schedule out further. 98% of Opendoor offers close on time because the transaction does not depend on buyer financing or appraisal contingencies.

You can compare Opendoor's Cash Offer against the comp range you pulled yourself. If the numbers are close, the Cash Offer gives you certainty and speed. If your comp research shows significantly higher potential value, listing traditionally gives you the chance to test the open market — with the trade-off of a longer timeline and less certainty.

Learn more about how iBuyers and agents work together and what a cash offer means in real estate.

When Opendoor isn't the right fit

Opendoor isn't for sellers whose homes have extensive custom upgrades — hand-built stone fireplaces, custom wine cellars, architect-designed additions — that do not show up in comp databases. If your home's value comes primarily from one-of-a-kind features rather than standard square footage and bedroom count, an agent CMA or traditional listing will capture more of that value because a human agent can market the story behind the upgrades. Opendoor's pricing model is built for homes where comp data is plentiful and reliable — and that covers the vast majority of single-family homes in the 50+ markets it serves, but not every home in every situation.