What Are Comparable Sales (Comps) and How Do They Affect Home Value?

Comparable sales, or 'comps,' are recently sold properties that appraisers and real estate agents use to determine a home's fair market value.

By Garret Merkley · Explainer · Aug 20, 2026

Branched from What to Do When Your Home Appraisal Comes in Low

Quick take

Comparable sales (comps) are recently sold homes similar to yours in location, size, and features.
Appraisers use comps to estimate a home's market value by making adjustments for differences.
Comps directly influence how much a lender will approve for a mortgage or refinance.
Understanding comps helps both buyers and sellers make informed real estate decisions.

Comparable sales, commonly known as "comps," are recently sold properties that share key similarities with a specific home being valued. Real estate professionals, especially appraisers, use these past transactions as a benchmark to estimate a home's current market value, providing an objective basis for pricing and lending decisions.

The Core of Appraisal: How Comps Work

When an appraiser evaluates a property, they don't just pull a number out of thin air. They start by identifying several recently sold homes that are most like the subject property. The goal is to find homes that a buyer would consider good alternatives, making them truly comparable.

The selection process for comps is meticulous. Appraisers typically look for homes sold within the last three to six months, ideally within a one-mile radius, though this can extend in rural areas. They consider a range of factors to ensure a fair comparison:

**Location:** Proximity to the subject property, often within the same neighborhood or school district.
**Size:** Similar square footage, number of bedrooms and bathrooms, and lot size.
**Age:** Homes built around the same time period.
**Condition:** Similar overall wear and tear, updates, and maintenance levels.
**Features:** Shared amenities like a garage, pool, finished basement, or specific architectural styles.
**Sale Date:** The more recent the sale, the more relevant the comp.

Once suitable comps are identified, the appraiser makes adjustments. This is where the art and science of appraisal come in. If a comp has a feature the subject property lacks (e.g., a pool), the appraiser will subtract the estimated value of that feature from the comp's sale price. Conversely, if the subject property has a feature a comp lacks (e.g., a newly renovated kitchen), the appraiser will add value to the comp's price. These adjustments bring the comparable properties as close as possible to the subject property, allowing for a more accurate valuation.

Why Comps Are Crucial for Your Home's Value

Comps are the bedrock of property valuation and play a critical role in almost every real estate transaction. For sellers, understanding comps helps set a realistic asking price that attracts buyers and ensures the home appraises for the sale price. Pricing too high without comp support can lead to a low appraisal, causing delays or even a deal to fall through.

For buyers, comps confirm that the price they're offering is fair and supported by the market. Lenders rely heavily on appraisal reports, which are built on comps, to ensure the property's value justifies the mortgage loan amount. If an appraisal comes in low, the lender may not approve the full loan, requiring the buyer to make up the difference or the seller to lower the price.

Beyond buying and selling, comps are vital for refinancing, property tax assessments, and even establishing insurance values. They provide a transparent, market-driven snapshot of what a property is worth at a given time.

Looking at Comps Like an Appraiser

Focus on recent sales (last 3-6 months). Older sales are less reliable.
Prioritize homes within a mile or two. Different neighborhoods can have vastly different values.
Compare homes with similar bedrooms, bathrooms, square footage, and lot size.
Consider condition and upgrades. A remodeled kitchen or new roof adds value.
Don't just look at the highest sales. A balanced view, including lower sales, provides a more accurate picture.

How far back do appraisers look for comps?

Typically, appraisers look for sales within the last three to six months. In a fast-moving market or an area with limited sales activity, they might extend this to nine or even twelve months, but recent sales are always preferred for accuracy.

How many comps are typically used in an appraisal?

An appraiser usually uses three to five primary comparable sales. They may also include additional listings or older sales for context, but the core valuation is based on a few strong, recent comparisons.

Can I find comps myself?

Yes, you can research public records for recent sales in your area, or work with a real estate agent who has access to MLS (Multiple Listing Service) data. While you can't perform an official appraisal, understanding local comps can help you gauge market value.

What if there aren't many good comps in my area?

In areas with unique properties or low sales volume, appraisers may need to broaden their search area or extend the timeframe for sales. They might also rely more on other valuation methods, though comps remain the primary approach when available. This can sometimes make an appraisal more challenging.

Do comps only matter when selling a home?

No, comps are important in many situations. They are crucial for buyers to ensure they're not overpaying, for homeowners looking to refinance, for property tax assessments, and for insurance purposes to determine replacement value. They provide a fundamental measure of market value.