How to Run Your Own Comps Analysis: Find Your True Home Value

Online home value estimates from Zillow, Redfin, and Realtor.com are convenient—but they can be off by $50,000-$100,000 or more. When you're making major financial decisions (selling, refinancing, getting a HELOC), you need to know your home's true value.

Professional appraisers use "comparables" (comps)—recently sold, similar homes in your area—to determine value. You can use the same methodology to understand your equity position before listing, refinancing, or tapping into a HELOC.

A 2025 study by the Appraisal Institute found that homeowners who conducted their own comps analysis before listing sold for an average of 3.2% more than those who relied solely on automated valuations—that's $15,000-$25,000 on a typical home.

What Are Comps and Why Do They Matter?

Comparable sales (comps) are recently sold homes that are similar to yours in:

• Location (neighborhood, school district, proximity)
• Size (square footage, bedrooms, bathrooms)
• Condition (age, updates, maintenance)
• Features (garage, lot size, finishes)

Appraisers use comps because they reflect what real buyers actually paid in real transactions—not algorithmic estimates or wishful thinking.

Why Comps Matter for Your Equity:

For Selling:

• Price too high: Home sits, eventually sells below market
• Price too low: Leave money on the table, lose equity
• Price right (using comps): Faster sale, maximum value

For HELOCs:

• Lenders order appraisals that use comps
• Understanding comps beforehand shows you likely capacity
• You can challenge low appraisals with your own analysis

For Refinancing:

• Appraisal determines loan-to-value ratio
• Higher appraisal = better rates, more cash-out potential
• Comps analysis helps you know what to expect

For Equity Planning:

• Accurate value = accurate equity calculation
• Helps you time refinancing, improvements, or sale decisions
• Shows whether you're building equity as expected

Step 1: Gather Data on Comparable Sales

Where to Find Comps:

Zillow.com:

• Search your address
• Click "See more homes" under "Comparable Sales"
• Filter by "Sold" (not "For Sale")
• Set date range: Last 6 months

Realtor.com:

• Search your address
• Scroll to "Nearby Recently Sold Homes"
• Filter by sold date, size, price

Redfin.com:

• Search your address
• Click "Nearby Homes"
• Filter to "Sold" within last 6 months
• Best interface for side-by-side comparisons

Public Records:

• County assessor/recorder website
• Search by address or neighborhood
• Shows sale prices, dates, property details

Local MLS (Through Realtor):

• Most accurate data
• Ask your realtor for a "Comparative Market Analysis" (CMA)
• Free if you're considering selling

What Time Frame to Use:

Standard: Last 6 months

• Reflects current market conditions
• Most appraisers use 3-6 month window

Hot/rising markets: Last 3 months

• Values changing rapidly
• Older comps may undervalue your home

Slow/stable markets: Last 12 months

• Broader dataset if few recent sales
• More stable pricing, less urgency

COVID/2020-2022 note: Avoid using 2021-2022 sales as comps in 2026—market conditions were abnormally hot. Stick to 2024-2026 sales.

Step 2: Select the Right Comps

Not all sold homes are good comps. Professional appraisers look for:

The Goldilocks Criteria:

Location (Most Important):

• Ideal: Same neighborhood, within 0.5 miles
• Acceptable: Adjacent neighborhood, same school district, within 1 mile
• Poor comp: Different school district, 2+ miles away

Size:

• Ideal: Within 10% of your square footage (if your home is 2,000 sq ft, look for 1,800-2,200)
• Acceptable: Within 20%
• Poor comp: More than 25% difference

Bedrooms/Bathrooms:

• Ideal: Exact match (3 bed / 2 bath = 3 bed / 2 bath)
• Acceptable: Within 1 bedroom OR 1 bathroom difference
• Poor comp: Significantly different (4/3 vs. 2/1)

Age/Condition:

• Ideal: Similar age (within 10 years), similar condition
• Acceptable: Similar age OR similar condition (older but renovated)
• Poor comp: Dramatically different (new construction vs. 60-year-old fixer)

Lot Size:

• Urban areas: Less important (most homes have small, similar lots)
• Suburban/rural: Important (0.25 acre vs. 2 acre lot is significant)
• Ideal: Within 25% of your lot size

Features:

• Garage (2-car vs. 1-car vs. none)
• Basement (finished vs. unfinished)
• Pool, porch, deck
• View (waterfront, mountain, golf course)

How Many Comps to Use:

Minimum: 3 comps (appraisers typically use 3-6) Ideal: 5-7 comps Maximum: 10 comps (too many dilutes analysis)

Pro tip: If you can't find 3 strong comps within 6 months, your home may be unique—consider expanding to 12 months or widening geographic range.

Step 3: Adjust for Differences

No two homes are identical. You need to adjust comp sale prices based on differences from your home:

The Adjustment Process:

If the comp has something your home doesn't:

• Subtract value (comp's sale price is higher than your home's value)

If your home has something the comp doesn't:

• Add value (your home is worth more than the comp's sale price)

Typical Adjustments (2026 National Averages):

Size:

• $75-150 per square foot (varies by market)
• Example: Comp is 200 sq ft larger → Subtract $15,000-30,000

Bedrooms:

• $10,000-30,000 per bedroom (depending on market)
• Example: Comp has extra bedroom → Subtract $15,000-25,000

Bathrooms:

• Full bath: $8,000-20,000
• Half bath: $3,000-8,000
• Example: Comp has extra full bath → Subtract $10,000-15,000

Garage:

• 1-car garage: $10,000-20,000
• 2-car garage: $20,000-35,000
• Example: Comp has 2-car, you have 1-car → Subtract $10,000-15,000

Condition:

• Updated kitchen: $15,000-40,000
• Updated bathrooms: $8,000-20,000 each
• New roof: $8,000-15,000
• Finished basement: $20-50 per sq ft
• Pool: $10,000-40,000 (market dependent)

Lot Size:

• $1-5 per square foot (market dependent)
• Example: Comp has 2,000 sq ft larger lot → Subtract $2,000-10,000

Location:

• Highly subjective—hardest to quantify
• Better school district: $25,000-100,000+
• Busier street: -$5,000-20,000
• Better view: $20,000-100,000+

Adjustment Example:

Your home:

• 2,000 sq ft, 3 bed, 2 bath, 2-car garage, 0.25 acre, original kitchen

Comp #1:

• Sold for $425,000
• 2,100 sq ft, 3 bed, 2 bath, 2-car garage, 0.25 acre, renovated kitchen
• Adjustments:
  • Larger by 100 sq ft: -$10,000 ($100/sq ft)
  • Renovated kitchen: -$25,000
  • Adjusted comp value: $390,000

Comp #2:

• Sold for $380,000
• 1,850 sq ft, 3 bed, 1.5 bath, 1-car garage, 0.25 acre, similar condition
• Adjustments:
  • Smaller by 150 sq ft: +$15,000
  • Missing half bath: +$5,000
  • Smaller garage: +$12,000
  • Adjusted comp value: $412,000

Comp #3:

• Sold for $405,000
• 2,000 sq ft, 4 bed, 2 bath, 2-car garage, 0.30 acre, similar condition
• Adjustments:
  • Extra bedroom: -$20,000
  • Larger lot: -$2,500
  • Adjusted comp value: $382,500

Average adjusted value: ($390,000 + $412,000 + $382,500) / 3 = $394,833

Your home's estimated value: $395,000

Step 4: Analyze Market Conditions

Comps reflect past sales. You need to account for current market direction:

Rising Market:

If homes are appreciating 0.5-1% per month:

• Comp sold 6 months ago: Add 3-6%
• Comp sold 3 months ago: Add 1.5-3%
• Comp sold 1 month ago: Add 0.5-1%

Example: Comp sold for $400,000 five months ago in rising market

• $400,000 × 1.04 (4% appreciation) = $416,000 adjusted

Declining Market:

If homes are depreciating:

• Apply same logic in reverse (subtract appreciation)

Example: Comp sold for $400,000 five months ago in declining market (-2%/month)

• $400,000 × 0.90 (10% decline) = $360,000 adjusted

How to Know Market Direction:

Check local data:

• Median sale price trends (city/MLS reports)
• Average days on market (declining = hotter market)
• Inventory levels (fewer homes = rising prices)

Resources:

• Local realtor monthly reports
• Zillow Market Reports (city level)
• Redfin Data Center
• Local news real estate sections

Step 5: Compare to Automated Valuations

Now compare your comps-based analysis to online estimates:

Your Analysis: $395,000

Zillow Zestimate: $385,000

• Your analysis is 2.6% higher

Redfin Estimate: $402,000

• Your analysis is 1.7% lower

Realtor.com Estimate: $390,000

• Your analysis is 1.3% higher

Average online estimate: $392,333

• Your analysis is 0.7% higher—very close alignment

When to Trust Your Analysis:

Your comps are stronger when:

• You found 5+ very similar comps within 6 months
• Adjustments are minimal (homes are truly comparable)
• Your result aligns with 2-3 online estimates
• You know specific features online algorithms miss (recent updates, neighborhood microclimates)

When to Question Your Analysis:

Be skeptical if:

• Your result is 10%+ higher than all online estimates (wishful thinking?)
• You could only find 1-2 weak comps
• Adjustments are large and subjective
• You're emotionally attached to a higher number

Solution: Get a professional opinion (realtor CMA or pre-appraisal) before making major decisions.

Using Your Comps Analysis for HELOC and Refinancing

HELOC Capacity Calculation:

Your comps analysis: $395,000

Lender will use:

• Ordered appraisal (which uses comps similar to yours)
• Typically 80% LTV for HELOCs (some go 85-90%)

Your current mortgage: $280,000

HELOC capacity:

• $395,000 × 0.80 = $316,000 (max combined loan)
• $316,000 - $280,000 = $36,000 HELOC capacity

If appraisal comes in at $415,000:

• $415,000 × 0.80 = $332,000
• $332,000 - $280,000 = $52,000 HELOC capacity

$20,000 appraisal difference = $16,000 borrowing capacity difference

Preparing for Your HELOC Appraisal:

Bring your comps analysis:

• Provide to appraiser at inspection
• Highlight strong recent comps
• Point out features that add value

Make sure appraiser sees:

• Recent updates (new HVAC, roof, appliances)
• Finished spaces (basement, attic, bonus rooms)
• Improvements you've made

Challenge low appraisals:

• If appraisal comes in below your analysis and online estimates
• Provide additional comps appraiser may have missed
• Request reconsideration of value

When Your Home Is Hard to Compare

Unique Properties:

Some homes don't have good comps:

• Waterfront/view properties: Few sales, unique features
• Historic homes: Character, restrictions
• Very large/small: Outliers in neighborhood
• Extensive custom work: Hard to value objectively

Solutions:

Expand search criteria:

• Go to 12-18 months of sales
• Widen geographic area (same school district, similar neighborhoods)
• Look for homes with some similar features, even if not perfect matches

Use price-per-square-foot as guide:

• Calculate average $/sq ft from nearby sales
• Apply to your square footage
• Adjust for condition/features

Example:

• Nearby comps averaging $200/sq ft
• Your home: 2,500 sq ft
• Base value: $500,000
• Add $50,000 for updates, view, premium lot
• Estimated value: $550,000

Get professional help:

• Realtor CMA (free if you're considering selling)
• Pre-listing appraisal ($400-600, worth it for unique properties)
• HELOC appraisal (lender pays, but happens after you apply)

Common Comps Analysis Mistakes to Avoid

1. Cherry-Picking Comps

The mistake: Only selecting comps that support your desired value

The fix: Use objective criteria, include comps above AND below your target

2. Ignoring Location Differences

The mistake: Using a comp from a worse neighborhood because the price is closer

The fix: Location is paramount—0.5 mile and different school district = weak comp

3. Over-Adjusting

The mistake: Adding value for every minor feature ($5,000 for landscaping, $3,000 for new paint, etc.)

The fix: Only adjust for major, quantifiable differences

4. Using Listing Prices

The mistake: Comparing to active listings (asking prices)

The fix: Only use SOLD prices—buyers' opinions don't matter, only what they actually paid

5. Emotional Attachment

The mistake: "My home is special, worth more than comps show"

The fix: Buyers don't care about your memories—they compare to alternatives

6. Ignoring Market Direction

The mistake: Using 6-month-old comps in rapidly changing market

The fix: Adjust for appreciation/depreciation, use recent comps

7. Skipping the Professional Opinion

The mistake: Acting on your DIY analysis without validation

The fix: Get at least one professional opinion (realtor or appraiser) before major decisions

Your Comps Analysis Action Plan

Week 1: Gather Data

• Search Zillow, Redfin, Realtor.com for sold comps (last 6 months)
• Find 5-10 potential comps
• Record: Address, sale date, price, sq ft, beds, baths, features
• Create spreadsheet or use template

Week 2: Analyze and Adjust

• Narrow to 3-5 best comps (location, size, condition)
• Calculate adjustments for each comp
• Determine adjusted comp values
• Average adjusted values = your estimated home value

Week 3: Validate and Plan

• Compare to online estimates (Zillow, Redfin, Realtor)
• If major discrepancy, review your adjustments
• Consider getting free realtor CMA for validation
• Calculate your equity: (Estimated Value × 0.80) - Mortgage Balance

Week 4: Take Action

• Get pre-qualified for HELOC with realistic value estimate
• Understand appraisal expectations
• Prepare comps to show appraiser
• Make decision: Refinance, HELOC, sell, or hold

Comps Analysis Tools and Templates

Spreadsheet Template:

Online Tools:

HomeLight Home Value Estimator:

• Combines MLS data with agent input
• More accurate than pure algorithms

Redfin My Home Dashboard:

• Track your home's value over time
• See new comps automatically

Zillow Zestimate:

• Convenient but can be inaccurate
• Use as data point, not gospel

ComeHome (by Zillow):

• Shows you're specifically shopping for homes to buy
• Good for finding comps in your search

Ready to Unlock Your Home's True Value?

Running your own comps analysis gives you confidence—whether you're selling, refinancing, or getting a HELOC. You'll know your true equity position and can make decisions based on reality, not algorithms.

Get pre-qualified for a HELOC today and see how much equity you can access:

✓ 3-minute pre-qualification
✓ No credit score impact
✓ Professional appraisal included
✓ See your real borrowing capacity

Get Pre-Qualified Now →

Your home's value is real equity you can use. Make sure you know exactly what you have.

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Sources:

• Appraisal Institute, Homeowner Valuation Study, 2025
• Zillow Research, Zestimate Accuracy Data
• National Association of Realtors, CMA Best Practices
• Federal Housing Finance Agency, Home Price Index
• Local MLS data and appraisal methodologies