What Are Real Estate Comps?
Comparable sales ("comps") are recently sold properties that are similar to a subject property in location, size, condition, and features. They are the primary data points used to estimate a property's current market value.
Whether you're making an offer on a wholesale deal, estimating after-repair value, or listing a renovated flip, your valuation is only as good as your comps.
Why Comps Matter for Investors
Comps are the foundation of every real estate investment decision. They determine:
- What a property is worth right now (as-is value)
- What it will be worth after repairs (ARV)
- How much you should offer on a deal
- Whether a market supports your investment thesis
Unlike a formal appraisal or BPO, running comps is something every investor should learn to do independently.
How to Run Comps Step by Step
- Identify the subject property. Note the address, square footage, bed/bath count, lot size, year built, and current condition.
- Define your search area. Start within 0.5 miles. In rural areas, you may need to expand to 1–2 miles.
- Set your time frame. Filter for sales within the last 3–6 months.
- Filter by property type. Match single-family to single-family, condo to condo, etc.
- Match size and features. Look for properties within 20% of the subject's square footage with similar bed/bath counts.
- Review and adjust. Analyze each comp's condition, features, and sale circumstances. Make adjustments for differences.
- Calculate your estimate. Use a weighted average, giving more weight to the most comparable sales.
Run comps in seconds, not hours
Revaluno's Comps Tool pulls and filters comparable sales automatically using AI — so you can focus on making offers.
Try the Comps Tool
Key Filtering Criteria
Not all sales are good comps. Use these filters to narrow your selection:
- Distance: 0.25–0.5 miles in urban/suburban areas
- Time: 3–6 months (extend to 12 months only if necessary)
- Square footage: Within 20% of the subject
- Bed/bath: Match count whenever possible
- Property type: Same type (SFR, condo, townhome)
- Condition: Similar renovation level and quality of finishes
- Sale type: Exclude distressed sales (foreclosures, short sales) unless that's your market
How to Adjust Comps
Adjustments bridge the gap between each comp and your subject property. The principle is simple: if the comp has a feature the subject doesn't, subtract value. If the subject has something the comp lacks, add value.
For a deeper discussion of adjustment methodology and common pitfalls, read our article on comping mistakes to avoid.
Tools for Running Comps
Investors typically use one or more of these sources:
- MLS access (via an agent or PropStream-style tool)
- County tax records for verified sale prices
- AI-powered platforms like Revaluno's AI CMA Tool that automate comp selection and adjustments
Manual comping takes 30–60 minutes per property. Automated tools can reduce that to under 2 minutes while maintaining accuracy.
Frequently Asked Questions
How many comps do I need?
Aim for 3–6 comparable sales. Fewer than 3 makes your estimate unreliable; more than 6 often introduces noise from less-similar properties.
How recent should comps be?
Ideally within 3–6 months. In slow markets, you may extend to 12 months, but always prioritize recency.
What if there are no good comps?
Expand your search radius slightly, extend the time frame, or consider adjusting comps from adjacent neighborhoods with similar characteristics.