Comping Takes Too Long
Traditional comping eats 45-90 minutes per property. Pulling comps, adjusting for features, calculating price per square foot, checking market sentiment. Most operators either rush through it and miss adjustments, or skip it entirely and guess.
The Claude comping skill compresses that into a single conversation. Give it an address. It pulls public records, finds comparable sales, sorts them into two buckets, applies feature adjustments, checks market conditions, and delivers a complete analysis with a confidence-banded ARV range.
The output is a 7-tab Excel workbook you can hand to a partner, lender, or contractor. Not a screenshot of a Zillow page. A structured report with the math trail visible at every step.
What It Produces
7-tab Excel workbook: Executive Summary, Subject Property, Comparable Sales, Adjustments Detail, Market Analysis, ARV Calculation, Sources and Notes. Plus a full in-context breakdown.
What You Need
Claude Pro ($20/mo), a property address, and optionally your own closed deal data for market calibration. That is it.
Download the Claude Comping Skill
Upload this .skill file to Claude Co-Work or Claude Projects to start comping properties instantly. Download from Google Drive
See all available skills → Claude Skills for REI
Turning on the comping skill in Claude. Click to zoom.
The Two-Bucket Method
Every comp goes into one of two buckets based on condition. The gap between them tells you what the market pays for renovation.
Bucket A: Unrenovated
Dated finishes, original condition, deferred maintenance. Similar age, size, and layout to subject property.
Bucket B: Renovated
Fully updated, flipped, or clearly modernized to current market standard. Verified via photos, remarks, or permits.
Bucket A Details
Select comps with similar size/plan, average or below-average condition, sold within 90 days (6 months max), arm's-length sales only. Calculate the Median PPSF_A (price per square foot for unrenovated properties).
Bucket B Details
Select comps that are flips or clearly modernized. Verify via photos, remarks, and permits. Quality-adjust if one comp is ultra-lux beyond typical. Calculate the Median PPSF_B (price per square foot for renovated properties).
MARKET PREMIUM FORMULA
Market Premium (%) = (PPSF_B - PPSF_A) / PPSF_A x 100%
Disclosure vs Non-Disclosure
The skill auto-detects which framework to use based on property address. Disclosure states have visible sold prices. Non-disclosure states hide them, requiring a triangulation method.
Two-Bucket Method (Standard)
Sold prices are publicly recorded. The skill pulls actual sale prices from MLS, county records, and aggregators (Zillow, Redfin). Comps are sorted into Bucket A and Bucket B using real sold data.
Confidence Band
±2-5% on final ARV. Tighter range because you are working with actual sold prices.
This is the framework used in the 5532 Joyce Ann example. Ohio is a full disclosure state.
Triangulation Method
Sold prices are not publicly recorded. The skill must derive estimated sold prices (ESP) using multiple methods before it can apply the Two-Bucket analysis.
Method A: Last List Price + DOM
Find the last list price before "Pending." Under 7 DOM = list price or 101%. 7-30 DOM = 97-100%. Over 30 DOM = 90-95%.
Method B: Deed of Trust Calculation
Find the loan amount from public records. Conventional: Loan / 0.80. FHA: Loan / 0.965. VA: Loan / 1.00.
Method C: Tax Value Ratio (Sanity Check)
Compare assessed value to list price ratios for active homes. Apply multiplier. Use only as confirmation, never as primary method.
Confidence Band
±5-7% on final ARV. Wider range because you are working with derived prices, not actual sold data.
Non-Disclosure States:
The 5532 Joyce Ann Comp Report
A 1961 brick ranch in Dayton, OH. 3 bed, 2 bath, 1,892 sqft. Dated condition, cosmetic rehab needed. The skill produced a 7-tab report. Here is every tab, broken down.
Executive Summary tab. Click to zoom.
What This Tab Shows
The executive summary is your one-page overview. Three sections at a glance:
Subject Property: Address, property type (Single Family, Brick Ranch), 1,892 sqft, 3/2, built 1961. Confirms the skill pulled the right property.
ARV Analysis Results: Final ARV of $265,000 with a range of $252,000 to $278,000. Moderate confidence. Post-renovation price per square foot of $150.53.
Market Snapshot: Balanced market. Median sale price $225,000, median PPSF $131. Average 34 days on market. 98% sale-to-list ratio. This tells you the market is not distressed and not overheated.
Subject Property tab. Click to zoom.
What This Tab Shows
Every data point the skill gathered about the subject property, organized into four sections:
Basic Information: Full address, city (Dayton), state (OH), ZIP (45415), county (Montgomery), subdivision (Harrison Township).
Property Characteristics: 1,892 sqft living area, 13,068 sqft lot, 3 bed / 2 bath, 1961 build, 1 story, 2-car attached garage, no pool, unfinished basement (mechanical/storage).
Current Condition: Dated. Cosmetic rehab needed. Renovation scope to be determined in a separate workflow.
Ownership and Legal: Individual owner, residential zoning, no HOA. Clean.
Comparable Sales tab. Click to zoom.
6 Comps, Two Buckets
The skill found 6 comparable sales within 2 miles, all sold in the last 90 days, all 3/2 brick ranches built between 1955-1975. Here is the full breakdown:
| # | Address | Date | Price | GLA | PPSF | Condition | Dist. | Adj. | Adj. Value | Bucket |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 5802 Sparkhill Dr | Dec 12 | $190,000 | 1,520 | $125.00 | Partial Update | 1.2 mi | +$22,000 | $212,000 | A |
| 2 | 6407 Woodville Dr | Nov 15 | $210,000 | 1,686 | $124.56 | Average | 1.5 mi | +$8,000 | $218,000 | A |
| 3 | 6012 Imperial Hills Dr | Jan 12 | $208,750 | 1,669 | $125.07 | Good/Maintained | 1.8 mi | +$9,000 | $217,750 | A |
| 4 | 6430 Oakhurst Pl | Dec 19 | $240,000 | 1,657 | $144.84 | Dated | 1.6 mi | +$10,000 | $250,000 | A |
| 5 | 701 Fredericksburg Dr | Dec 29 | $239,900 | 1,464 | $163.87 | Updated | 0.8 mi | +$17,000 | $256,900 | B |
| 6 | 6029 Imperial Hills Dr | Dec 29 | $210,000 | 1,411 | $148.83 | Good | 1.8 mi | +$19,000 | $229,000 | B |
TWO-BUCKET RESULTS
Bucket A (4 comps): Median PPSF $125.03 | Avg $129.87
Bucket B (2 comps): Median PPSF $156.35 | Avg $156.35
Renovation Premium: 20.4%
Adjustments Detail tab. Click to zoom.
Line-by-Line Adjustments
Every comp gets adjusted to make it comparable to the subject property. The skill applied three types of adjustments across the 6 comps:
GLA Adjustments
+$78,000 total. The subject (1,892 sqft) was larger than every comp. Comp 6 was 481 sqft smaller, earning the biggest adjustment (+$19,000).
Condition Adjustments
-$3,000 total. One comp (5802 Sparkhill) had newer roof and windows than the subject. The adjustment accounts for that advantage.
Basement Adjustments
+$10,000 total. The subject has an unfinished basement. Comp 1 (5802 Sparkhill) only had a crawl space. Adjustment reflects the storage and expansion value.
TOTAL ADJUSTMENTS ACROSS ALL COMPS
GLA +$78,000 | Condition -$3,000 | Basement +$10,000 = Net +$85,000
Market Analysis tab. Click to zoom.
Market Health Check
Before the skill calculates ARV, it reads the market. The Market Analysis tab has three sections:
Market Metrics
Balanced market. Median price $225,000, PPSF $131. 34 avg DOM. 98% sale-to-list ratio. 45 active listings, 22 pending, 3.5 months of inventory.
Market Trends
3-month: Stable (+1.2%). 6-month: Slight appreciation (+3.8%). DOM stable at 30-40 days. Inventory balanced.
ARV Calculation tab. Click to zoom.
The 9-Step ARV Math
This is where the skill shows its work. Every number traces back to a specific data point. No black boxes.
Confidence Analysis
Moderate confidence. ±5.0% band. ARV Low: $252,000. ARV High: $278,000.
Why -2% Sentiment?
Balanced market with 98% sale-to-list ratio. Not hot enough for a positive bump, but the slight positive trend (+1.2% 3mo) prevents a deeper cut.
Sources and Notes tab. Click to zoom.
The Paper Trail
Every good comp report is auditable. This tab documents where the data came from and what constraints were applied.
Data Sources
Zillow, Sibcy Cline MLS, Coldwell Banker MLS, ATTOM Data, Montgomery County Auditor, Homes.com, and subject property due diligence photos.
Search Parameters
90-day window (Dec 2025 - Feb 2026). 2-mile radius. GLA range 1,400-2,150 sqft. Year built 1955-1975. Harrison Twp / Butler Twp / North Dayton.
Key Recommendations
The skill flagged several items for verification before making an offer:
- Verify GLA with county assessor. Records show 1,652 vs 1,892 sqft discrepancy.
- Get actual basement square footage and finish level. Unfinished adds $5-10K, finished could add $15-25K.
- R-22 A/C condenser needs full replacement (refrigerant phased out).
- Electrical panel should be evaluated (original 1959 panel).
- Run title search. Check permit history for unpermitted additions.
- Wholesale price target: $205,000-$215,000. Selling points: new furnace, 1,892 sqft, sunroom, fenced yard.
Adjustment Cheatsheet
The skill uses these ranges when adjusting comps. Values shift by price tier and climate. Expand each category to see the full table.
| Feature | Under $500K | Over $500K |
|---|---|---|
| Bedroom | +$10,000 | +$25,000 |
| Full Bath | ±$10,000 | ±$10,000 |
| Half Bath | ±$5,000 | ±$5,000 |
| Feature | Standard | Hot/Cold Climate |
|---|---|---|
| Garage | $10,000-$15,000 | $20,000-$25,000 |
| Carport | $5,000-$7,500 | $10,000 |
Climate note: Use high end in very hot (AZ, NV, TX) or very cold (IL, MN, WI) markets. Hail-prone areas (TX, OK, CO) make garage vs carport a major differentiator.
| Issue | Under $500K | Over $500K |
|---|---|---|
| Backing busy road | -$10,000 | -10% to -15% |
| Fronting busy road | -$20,000 | -20% |
| Commercial adjacency | -$10K to -$20K | -10% to -15% |
| Feature | Under $500K | Over $500K |
|---|---|---|
| Pool (hot climate) | +$20K to +$40K | +$20K to +$40K |
| Pool (cold climate) | +$5K to +$15K | Negative possible |
| Extra 5,000 sqft lot | $5K-$10K | $30K-$50K |
| Water view | +$20K-$50K | +$50K-$150K |
Basements are not counted as GLA by appraisers. Value depends on finish level:
| Finish Level | Value (% of Above-Grade PPSF) |
|---|---|
| Finished to same quality | ~50% |
| Finished with drop ceilings | ~35-40% |
| Partially finished | ~25-35% |
| Unfinished | ~10-15% |
ADUs: Not separately deeded = ~50% of equivalent value. Separately deeded/titled = 100% at local PPSF.
| Issue | Adjustment |
|---|---|
| Minor cracks (cosmetic) | -$5,000 to -$10,000 |
| Moderate issues | -$15,000 to -$25,000 |
| Major repair needed | -$25,000 to -$40,000+ |
| Previous repair (documented) | -$5,000 to -$10,000 |
Draw Your Polygon in SiftMap
The comping skill works with any address. But if you want to constrain where it looks for comps, draw a polygon in SiftMap first.
SiftMap polygon with investor transaction filter. Click to zoom.
Why Draw a Polygon?
The skill's default search uses a radius from the subject property. That works in most markets. But in block-by-block markets where values shift street to street, a polygon gives you precision. You are telling the skill: "Only look inside these boundaries."
The golden rule of comping: do not cross major roads. Thick yellow lines on the map are value boundaries. The polygon lets you enforce that.
Investor Transaction Filter
Toggle the investor transaction filter in SiftMap to see what investors are actually paying in the area. These are real acquisition prices, not retail sales. Gives you ground truth for your wholesale price target.
Edit to Refine
The default polygon is accurate enough for most markets universally. But you can edit it to focus on a specific sub-area for more refined results. Narrow the polygon to 3-4 blocks around your subject for hyper-local comps.
Customize with Your Own Deals
The default adjustment tables are national averages. Your closed deals are ground truth for your specific market. Feed them to the skill and it calibrates automatically.
Editing the comping skill in Claude Co-Work. Click to zoom.
How It Works
Open the comping skill in Claude Co-Work (or Claude Projects). Add 3-5 properties you have closed in your target market. For each property, include:
- Property address and basic specs (beds, baths, sqft, year built)
- Your purchase price (what you actually paid)
- Rehab cost (actual spend, not estimate)
- Final sold price or appraised ARV (what it actually sold for or appraised at)
- Any notable adjustments (pool added, garage converted, foundation repaired)
The skill uses your closed deals to recalibrate its adjustment ranges, market sentiment assumptions, and confidence bands for your area. Instead of using national averages for "garage adds $10-15K," it learns that in your market, a 2-car garage adds $18K based on your actual data.
Draft Your Calibration Prompt
Use the field below to draft your calibration data. Include 3-5 closed deals with the details listed above.
Do This
Feed real closed deals with exact numbers: purchase price, rehab spend, final sold price.
Include 3-5 properties from the same market or sub-market.
Note any unusual features (pool added, foundation repair, lot split).
Not This
Do not just tell Claude "my market is hot" without data to back it up.
Do not use deals from different cities or states as calibration data.
Do not mix flips with buy-and-hold rentals. Different exit strategies, different comps.
Key Terms
Click any card to flip and see the definition.
ARV
Click to flip
After-Repair Value
The estimated market value of a property after all renovations are complete. Calculated by applying the renovated PPSF to the subject's GLA, adjusted for market sentiment and feature differences.
PPSF
Click to flip
Price Per Square Foot
Sale price divided by gross living area (GLA). The foundational metric for comparing properties of different sizes. Always compare PPSF within the same micro-market.
Two-Bucket Method
Click to flip
Comp Sorting Framework
Sort comps into Bucket A (unrenovated/dated) and Bucket B (renovated/flipped). The gap between median PPSF values reveals the market premium for renovation in that micro-market.
Market Premium
Click to flip
Renovation Spread
The percentage difference between renovated and unrenovated PPSF. Formula: (PPSF_B - PPSF_A) / PPSF_A x 100%. Typical range: 10-30%. Not a rehab cost estimate.
GLA
Click to flip
Gross Living Area
Above-grade living space measured in square feet. Basements are excluded from GLA. This is the number used for PPSF calculations and comp matching.
Comp Set Tightening
Click to flip
Filter Constraints
Hard filters applied before selecting comps: 90 days max age, same subdivision, ±250 sqft GLA, ±10 years build, matching elevation style. Do not cross major roads.
Price Triangulation
Click to flip
Non-Disclosure Method
Used in 12 states where sold prices are hidden. Derives estimated sold prices using Last List Price + DOM logic, Deed of Trust reverse math, and Tax Value ratios as a sanity check.
Confidence Band
Click to flip
ARV Range Indicator
The margin of error around the final ARV. Disclosure states: ±2-5%. Non-disclosure states: ±5-7%. Wider bands mean more uncertainty in the underlying data.
Feature Adjustments
Click to flip
Comp Normalization
Dollar or percentage adjustments applied to comps to account for differences from the subject property. Categories: GLA, bedrooms, bathrooms, garage, pool, lot size, traffic, condition, basement.
Disclosure State
Click to flip
Public Sale Prices
States where sold prices are publicly recorded (38 states + DC). The skill uses the standard Two-Bucket method with actual sold data. Ohio, California, Florida, and most states are disclosure states.
Test Your Understanding
7 questions on the comping framework. No trick questions. No case study recall.
1. What does the Two-Bucket method separate comps into?
2. What does the Market Premium measure?
3. How does the skill handle non-disclosure states?
4. What is the preferred maximum age for comparable sales?
5. Why would you draw a polygon in SiftMap?
6. What is the best way to calibrate the skill for your market?
7. What confidence band applies to non-disclosure states?
Resources
Tools, references, and related guides.
Download the Comping Skill
The .skill file for Claude. Upload to Co-Work or Projects to start comping.
Claude Pro
$20/mo. All you need to run the comping skill. No Max plan required.
Rehab Estimator Workflow
Companion guide: rehab estimation, finish tiers, scoping, deal economics.
Deal Flow Tech Stack SOP
Complete tool stack with pricing for every blueprint.
Case Studies
Real operator results across all four blueprints.
Critical Resource Hub
83 tools and resources across all 5 days of the Deal Flow Challenge.
Rehab Estimator Workflow
Turn inspection photos into contractor-grade rehab estimates with the Claude Rehab Estimator skill.