The Ultimate Guide to Real Estate Comps: Finding and Analyzing Comparable Sales

Why Comps Are Everything

Every number in your deal analysis — ARV, MAO, profit projection — flows from comparable sales. Getting comps wrong means getting everything wrong. This guide covers the complete process from finding comps to making adjustments to arriving at a defensible value.

Where to Find Comps

MLS (Best Source)

The Multiple Listing Service has the most accurate, complete sales data. Access through: your own real estate license, an investor-friendly agent, or MLS-connected data providers. MLS data includes sale price, photos, property details, days on market, seller concessions, and agent notes.

County Records

Public records show every recorded sale. Available through: county assessor website, county recorder's office, and data aggregators. Less detail than MLS but always available and free.

Data Providers

Bricked.ai, PropStream, BatchLeads, and others aggregate public records and MLS data into investor-friendly platforms. Cost: $50-200/month but saves significant time.

Selecting Good Comps

Not every recent sale is a good comp. Your comps should match your subject property on these criteria:

Location: Within 0.5 Miles

Same neighborhood, similar street, comparable surroundings. Expand to 1 mile only if 0.5 miles doesn't produce enough results. Never cross school district boundaries, major roads, or dramatic neighborhood transitions.

Recency: Last 6 Months

Recent sales reflect current market conditions. Expand to 12 months only if necessary. In rapidly changing markets, prioritize the most recent sales.

Size: Within 20%

A 1,200 sqft subject should use comps between 960-1,440 sqft. Larger differences require significant adjustments that reduce reliability.

Type: Match Exactly

Single-family to single-family. Townhome to townhome. Duplex to duplex. Never use a different property type as a comp.

Condition: Match Your Target

For ARV: use renovated comps (what fixed-up homes sell for). For as-is value: use unrenovated comps.

Making Adjustments

No two properties are identical. Adjust each comp based on how it differs from your subject:

Square Footage

$40-80/sqft depending on market. A comp that's 100 sqft larger than your subject gets a negative adjustment of $4,000-8,000.

Bedrooms

$5,000-10,000 per bedroom difference. Going from 2 to 3 bedrooms adds more value than going from 4 to 5.

Bathrooms

$3,000-8,000 per bathroom difference. Half-bath differences: $1,500-4,000.

Garage

$5,000-15,000 depending on market and type (attached vs. detached, 1-car vs. 2-car).

Lot Size

$1,000-5,000 for significant differences in residential areas. More impactful in suburban and rural markets.

Condition/Quality

$5,000-25,000 depending on the gap between comp condition and your subject's target condition.

Age/Updates

$3,000-10,000 for significantly newer or recently updated comps compared to an older, un-updated subject.

The Adjustment Process

For each comp:

1. Start with the comp's sale price
2. Add positive adjustments (comp is inferior to your subject)
3. Subtract negative adjustments (comp is superior to your subject)
4. Result: adjusted sale price

Example: Comp sold for $185,000. Your subject has 1 fewer bathroom (-$5,000), no garage (-$10,000), but is 100 sqft larger (+$6,000). Adjusted: $185,000 - $5,000 - $10,000 + $6,000 = $176,000.

Arriving at Your Value

1. Adjust all 3-5 comps
2. Average the adjusted values
3. Round conservatively (down for buying, up for selling)
4. Cross-check with $/sqft for the neighborhood
5. Validate with active listings and DOM trends

The Bottom Line

Accurate comps are the foundation of profitable investing. Pull from MLS or reliable data sources. Select comps within 0.5 miles, 6 months, 20% size, and matching type. Adjust for every difference. Average conservatively. Validate with $/sqft and market trends. Master this process and you'll never overpay for a property.