ARV Calculator & Comp Validation

Get Accurate ARVs Without Guessing

AI-powered After Repair Value calculation using live MLS comps, automated adjustments, and confidence-weighted valuations.

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The single most consequential number in any fix-and-flip or wholesale deal is the After Repair Value. Get the ARV right, and your offer, your rehab budget, and your profit margin all fall into alignment. Get it wrong — even by 10% — and a deal that looked like a winner on paper becomes a loss. Despite this, most investors rely on imprecise methods for estimating ARV: picking comparable sales by proximity alone, using raw sale prices without adjustments, or relying on Zillow's Zestimate, which is a consumer tool that does not apply the appraisal-grade methodology that lenders and serious investors require.

The ARV Calculator & Comp Validation Engine applies the same fundamental methodology used by licensed appraisers — pulling comparable sales, making condition and feature adjustments to each comp, and deriving an adjusted value per square foot — but at the speed of software and with the consistency of an AI that never rushes, never cuts corners, and always applies conservative bias when the data is thin.

The engine pulls 6 to 12 months of sold comparables within a 0.5-mile radius of the subject property, filtered by property type, bedroom/bathroom count, and square footage range. Each comparable is then adjusted individually for the differences between the comp and the subject: square footage, condition grade, bedroom/bathroom count, lot size, garage presence, pool, age, and other relevant features. Adjustments are made using a market-calibrated per-unit cost methodology — not generic national averages.

The final ARV is calculated as the median of the adjusted comp values — not the mean — to protect against distortion from outlier sales. A confidence score of High, Medium, or Low is assigned based on the number and quality of available comps, and a 5% downward market uncertainty adjustment is applied to all ARV estimates by default. If fewer than 3 valid comps are found after filtering and adjustment, the system explicitly flags the result as "Insufficient Comp Data" and recommends a manual appraisal.

Input Parameters

Parameter

Type

Required

Description

subject_address

String

Yes

Full property address of the subject property

property_type

String

Yes

SFR, Condo, Townhome, MFR_2-4

bedroom_count

Integer

Yes

Number of bedrooms in subject property (post-repair)

bathroom_count

Float

Yes

Number of bathrooms (0.5 increments; e.g., 2.5)

grosslivingarea_sqft

Integer

Yes

Post-repair gross living area in square feet (above grade)

lotsizesqft

Integer

No

Lot size in square feet (required for SFR)

garage_spaces

Integer

No

Number of enclosed garage spaces; default 0

pool

Boolean

No

Does the subject have a pool (post-repair)?

year_built

Integer

Yes

Year built of subject property

condition_grade

String

Yes

C1 (New), C2 (Excellent), C3 (Good), C4 (Average), C5 (Fair), C6 (Poor) — FNMA condition scale

compsearchradius_miles

Float

No

Search radius for comps; default 0.5; expanded to 1.0 if insufficient comps found

complookbackmonths

Integer

No

Months of sales history to include; default 6; expanded to 12 if insufficient

adjustment_methodology

String

No

marketcalibrated (default) or manualoverride

marketuncertaintyadjustment

Float

No

Conservative downward adjustment applied to final ARV; default 5%

output_format

String

Yes

fullreport, summary, crmpush, or all

Processing Methodology

Step 1 — Comp Pull. The AI queries the MLS sold data feed for the target market, filtered to:

  • Same property type as subject

  • Within configured search radius (default 0.5 mile, auto-expands to 1.0 mile if fewer than 6 comps found at 0.5)

  • Sold within configured lookback period (default 6 months, auto-expands to 12 months if fewer than 6 comps at 6 months)

  • Gross living area within ±25% of subject GLA

  • Same bedroom count ±1

The raw comp pool is filtered further to exclude:

  • Distress sales (foreclosure auction, REO bank sale, short sale) — these are not arms-length transactions and would artificially depress ARV

  • Sales with no verified sale price (listed as non-public or confidential)

  • Sales where the buyer and seller share the same surname (potential related-party transaction)

Step 2 — Adjustment Calculation. For each comp, the AI calculates adjustments for the following value differences between the comp and the subject property:

Adjustment Factor

Method

Gross Living Area

Market-calibrated per-sqft adjustment based on active sales in the market; applied linearly

Condition Grade

Paired-sales analysis: C3 vs C4 spread in market; typical range $8–$25 per sqft depending on market

Bedroom Count

Market-calibrated per-bedroom adjustment

Bathroom Count

Market-calibrated per-bathroom adjustment

Lot Size

Per-sqft land value, applied only for differences >15% of subject lot size

Garage

Per-space value; market-calibrated; typically $5,000–$18,000 per space

Pool

Market-calibrated pool contribution; varies significantly by climate market

Age/Year Built

Applied for comps >10 years age difference from subject

Location Adjustment

Applied manually if comp is in materially different neighborhood or school district zone

Step 3 — Adjusted Value Calculation. For each comp:

```

Adjusted Sale Price = Actual Sale Price + Sum of All Adjustments

Adjusted $/sqft = Adjusted Sale Price ÷ Comp GLA

```

Step 4 — Outlier Exclusion. Any comp whose adjusted value falls more than 2 standard deviations from the mean adjusted value of the comp set is flagged as an outlier and excluded from the final ARV calculation (retained in the report for transparency, marked with ⚠ OUTLIER).

Step 5 — ARV Derivation.

```

ARV (pre-adjustment) = Median of adjusted sale prices of valid comps

ARV (final) = ARV (pre-adjustment) × (1 − Market Uncertainty Adjustment)

= ARV (pre-adjustment) × 0.95 (with default 5% adjustment)

```

Step 6 — Confidence Score Assignment.

Condition

Confidence Score

6+ valid comps, tight adjustment range, sales within 90 days

HIGH

3–5 valid comps, moderate adjustment range, or sales 91–180 days

MEDIUM

Fewer than 3 valid comps, or high adjustment variance

LOW — Manual appraisal recommended

Output Format

ARV Summary:

```

Subject Property: 1847 W Elm St, Tempe AZ 85281

Property Type: SFR | 3bd/2ba | 1,420 sqft | C4 (Average → C3 Post-Repair)

Analysis Date: [Date]

ARV Estimate (Final, Conservative): $312,500

ARV Pre-Adjustment Median: $328,947

Market Uncertainty Adjustment Applied: -5% (-$16,447)

Confidence Score: MEDIUM (4 valid comps, 6-month lookback)

Range: $298,000 – $334,000 (adjusted comp range)

Recommended Offer at 70% ARV: $218,750

```

Comparable Sales Analysis Table:

Comp

Address

Sale Date

Sale Price

GLA sqft

$/sqft

GLA Adj

Condition Adj

Bath Adj

Garage Adj

Total Adj

Adj. Value

Adj $/sqft

Status

1

1920 W Elm St

45 days ago

$328,000

1,380

$237.68

+$8,400

$0

$0

$0

+$8,400

$336,400

$236.90

Valid

2

1755 W Oak Ave

67 days ago

$318,500

1,510

$210.93

-$11,400

+$14,200

$0

-$8,500

-$5,700

$312,800

$220.28

Valid

3

2103 S College Ave

89 days ago

$341,000

1,395

$244.44

+$7,000

$0

+$4,200

$0

+$11,200

$352,200

$248.03

⚠ OUTLIER

4

1612 W 4th St

112 days ago

$309,000

1,440

$214.58

-$1,200

+$14,200

$0

$0

+$13,000

$322,000

$223.61

Valid

5

1980 S Terrace Rd

158 days ago

$305,000

1,350

$225.93

+$10,800

$0

$0

$0

+$10,800

$315,800

$222.39

Valid

Median Adjusted Value (excl. outlier): $328,947 | ARV Final (−5%): $312,500

Conservative Bias Methodology

  1. Median, Not Mean. The ARV is calculated from the median of adjusted comp values. The mean is susceptible to distortion from high outliers (often cosmetically renovated properties or new construction that inflate the average). The median is more representative of the center of the market and less vulnerable to outlier influence.

  1. 5% Market Uncertainty Adjustment. Even when the comp analysis is strong, the AI applies a default 5% downward adjustment to the final ARV. This accounts for: (a) the time between comp sales and the projected sale date, (b) market volatility in the preceding 90 days, (c) uncertainty in the condition assessment when photos are not available, and (d) the general principle that it is better to be pleasantly surprised than to over-promise.

  1. Outlier Exclusion. Any comp more than 2 standard deviations from the mean is flagged and excluded. This prevents a single anomalous sale from inflating the ARV estimate.

  1. Distress Sale Exclusion. REO, foreclosure auction, and short sales are excluded from the comp pool. These transactions occur under compulsion and do not represent true market value — including them would artificially deflate the ARV and make deals appear worse than they are, which while seemingly "conservative" actually distorts the analysis in a different way.

  1. Insufficient Comps Flag. When fewer than 3 valid comps remain after all filters, the tool does not produce an ARV estimate. Instead, it returns an explicit "Insufficient Comp Data" flag with a recommendation to obtain a professional appraisal, a drive-by BPO, or a manual comp analysis from a local expert. A number produced from weak data is worse than no number at all.

CRM Integration

  • Attaches full ARV report as a note to the Property record in CRM

  • Populates custom fields: ARVEstimate, ARVConfidence, CompCount, ARVDate

  • Triggers recalculation reminder if ARV is more than 90 days old

  • Feeds ARV value directly into Deal Margin & ROI Scenario Modeler if pipeline integration is active

Parameter

Type

Required

Description

subject_address

String

Yes

Full property address of the subject property

property_type

String

Yes

SFR, Condo, Townhome, MFR_2-4

bedroom_count

Integer

Yes

Number of bedrooms in subject property (post-repair)

bathroom_count

Float

Yes

Number of bathrooms (0.5 increments; e.g., 2.5)

grosslivingarea_sqft

Integer

Yes

Post-repair gross living area in square feet (above grade)

lotsizesqft

Integer

No

Lot size in square feet (required for SFR)

garage_spaces

Integer

No

Number of enclosed garage spaces; default 0

pool

Boolean

No

Does the subject have a pool (post-repair)?

year_built

Integer

Yes

Year built of subject property

condition_grade

String

Yes

C1 (New), C2 (Excellent), C3 (Good), C4 (Average), C5 (Fair), C6 (Poor) — FNMA condition scale

compsearchradius_miles

Float

No

Search radius for comps; default 0.5; expanded to 1.0 if insufficient comps found

complookbackmonths

Integer

No

Months of sales history to include; default 6; expanded to 12 if insufficient

adjustment_methodology

String

No

marketcalibrated (default) or manualoverride

marketuncertaintyadjustment

Float

No

Conservative downward adjustment applied to final ARV; default 5%

output_format

String

Yes

fullreport, summary, crmpush, or all

Parameter

Type

Required

Description

subject_address

String

Yes

Full property address of the subject property

property_type

String

Yes

SFR, Condo, Townhome, MFR_2-4

bedroom_count

Integer

Yes

Number of bedrooms in subject property (post-repair)

bathroom_count

Float

Yes

Number of bathrooms (0.5 increments; e.g., 2.5)

grosslivingarea_sqft

Integer

Yes

Post-repair gross living area in square feet (above grade)

lotsizesqft

Integer

No

Lot size in square feet (required for SFR)

garage_spaces

Integer

No

Number of enclosed garage spaces; default 0

pool

Boolean

No

Does the subject have a pool (post-repair)?

year_built

Integer

Yes

Year built of subject property

condition_grade

String

Yes

C1 (New), C2 (Excellent), C3 (Good), C4 (Average), C5 (Fair), C6 (Poor) — FNMA condition scale

compsearchradius_miles

Float

No

Search radius for comps; default 0.5; expanded to 1.0 if insufficient comps found

complookbackmonths

Integer

No

Months of sales history to include; default 6; expanded to 12 if insufficient

adjustment_methodology

String

No

marketcalibrated (default) or manualoverride

marketuncertaintyadjustment

Float

No

Conservative downward adjustment applied to final ARV; default 5%

output_format

String

Yes

fullreport, summary, crmpush, or all

Processing Methodology

Step 1 — Comp Pull. The AI queries the MLS sold data feed for the target market, filtered to:

  • Same property type as subject

  • Within configured search radius (default 0.5 mile, auto-expands to 1.0 mile if fewer than 6 comps found at 0.5)

  • Sold within configured lookback period (default 6 months, auto-expands to 12 months if fewer than 6 comps at 6 months)

  • Gross living area within ±25% of subject GLA

  • Same bedroom count ±1

The raw comp pool is filtered further to exclude:

  • Distress sales (foreclosure auction, REO bank sale, short sale) — these are not arms-length transactions and would artificially depress ARV

  • Sales with no verified sale price (listed as non-public or confidential)

  • Sales where the buyer and seller share the same surname (potential related-party transaction)

Step 2 — Adjustment Calculation. For each comp, the AI calculates adjustments for the following value differences between the comp and the subject property:

Adjustment Factor

Method

Gross Living Area

Market-calibrated per-sqft adjustment based on active sales in the market; applied linearly

Condition Grade

Paired-sales analysis: C3 vs C4 spread in market; typical range $8–$25 per sqft depending on market

Bedroom Count

Market-calibrated per-bedroom adjustment

Bathroom Count

Market-calibrated per-bathroom adjustment

Lot Size

Per-sqft land value, applied only for differences >15% of subject lot size

Garage

Per-space value; market-calibrated; typically $5,000–$18,000 per space

Pool

Market-calibrated pool contribution; varies significantly by climate market

Age/Year Built

Applied for comps >10 years age difference from subject

Location Adjustment

Applied manually if comp is in materially different neighborhood or school district zone

Step 3 — Adjusted Value Calculation. For each comp:

```

Adjusted Sale Price = Actual Sale Price + Sum of All Adjustments

Adjusted $/sqft = Adjusted Sale Price ÷ Comp GLA

```

Step 4 — Outlier Exclusion. Any comp whose adjusted value falls more than 2 standard deviations from the mean adjusted value of the comp set is flagged as an outlier and excluded from the final ARV calculation (retained in the report for transparency, marked with ⚠ OUTLIER).

Step 5 — ARV Derivation.

```

ARV (pre-adjustment) = Median of adjusted sale prices of valid comps

ARV (final) = ARV (pre-adjustment) × (1 − Market Uncertainty Adjustment)

= ARV (pre-adjustment) × 0.95 (with default 5% adjustment)

```

Step 6 — Confidence Score Assignment.

Condition

Confidence Score

6+ valid comps, tight adjustment range, sales within 90 days

HIGH

3–5 valid comps, moderate adjustment range, or sales 91–180 days

MEDIUM

Fewer than 3 valid comps, or high adjustment variance

LOW — Manual appraisal recommended

Output Format

ARV Summary:

```

Subject Property: 1847 W Elm St, Tempe AZ 85281

Property Type: SFR | 3bd/2ba | 1,420 sqft | C4 (Average → C3 Post-Repair)

Analysis Date: [Date]

ARV Estimate (Final, Conservative): $312,500

ARV Pre-Adjustment Median: $328,947

Market Uncertainty Adjustment Applied: -5% (-$16,447)

Confidence Score: MEDIUM (4 valid comps, 6-month lookback)

Range: $298,000 – $334,000 (adjusted comp range)

Recommended Offer at 70% ARV: $218,750

```

Comparable Sales Analysis Table:

Comp

Address

Sale Date

Sale Price

GLA sqft

$/sqft

GLA Adj

Condition Adj

Bath Adj

Garage Adj

Total Adj

Adj. Value

Adj $/sqft

Status

1

1920 W Elm St

45 days ago

$328,000

1,380

$237.68

+$8,400

$0

$0

$0

+$8,400

$336,400

$236.90

Valid

2

1755 W Oak Ave

67 days ago

$318,500

1,510

$210.93

-$11,400

+$14,200

$0

-$8,500

-$5,700

$312,800

$220.28

Valid

3

2103 S College Ave

89 days ago

$341,000

1,395

$244.44

+$7,000

$0

+$4,200

$0

+$11,200

$352,200

$248.03

⚠ OUTLIER

4

1612 W 4th St

112 days ago

$309,000

1,440

$214.58

-$1,200

+$14,200

$0

$0

+$13,000

$322,000

$223.61

Valid

5

1980 S Terrace Rd

158 days ago

$305,000

1,350

$225.93

+$10,800

$0

$0

$0

+$10,800

$315,800

$222.39

Valid

Median Adjusted Value (excl. outlier): $328,947 | ARV Final (−5%): $312,500

Conservative Bias Methodology

  1. Median, Not Mean. The ARV is calculated from the median of adjusted comp values. The mean is susceptible to distortion from high outliers (often cosmetically renovated properties or new construction that inflate the average). The median is more representative of the center of the market and less vulnerable to outlier influence.

  1. 5% Market Uncertainty Adjustment. Even when the comp analysis is strong, the AI applies a default 5% downward adjustment to the final ARV. This accounts for: (a) the time between comp sales and the projected sale date, (b) market volatility in the preceding 90 days, (c) uncertainty in the condition assessment when photos are not available, and (d) the general principle that it is better to be pleasantly surprised than to over-promise.

  1. Outlier Exclusion. Any comp more than 2 standard deviations from the mean is flagged and excluded. This prevents a single anomalous sale from inflating the ARV estimate.

  1. Distress Sale Exclusion. REO, foreclosure auction, and short sales are excluded from the comp pool. These transactions occur under compulsion and do not represent true market value — including them would artificially deflate the ARV and make deals appear worse than they are, which while seemingly "conservative" actually distorts the analysis in a different way.

  1. Insufficient Comps Flag. When fewer than 3 valid comps remain after all filters, the tool does not produce an ARV estimate. Instead, it returns an explicit "Insufficient Comp Data" flag with a recommendation to obtain a professional appraisal, a drive-by BPO, or a manual comp analysis from a local expert. A number produced from weak data is worse than no number at all.

CRM Integration

  • Attaches full ARV report as a note to the Property record in CRM

  • Populates custom fields: ARVEstimate, ARVConfidence, CompCount, ARVDate

  • Triggers recalculation reminder if ARV is more than 90 days old

  • Feeds ARV value directly into Deal Margin & ROI Scenario Modeler if pipeline integration is active

  • Attaches full ARV report as a note to the Property record in CRM

  • Populates custom fields: ARVEstimate, ARVConfidence, CompCount, ARVDate

  • Triggers recalculation reminder if ARV is more than 90 days old

  • Feeds ARV value directly into Deal Margin & ROI Scenario Modeler if pipeline integration is active

  • Defend your number. The full adjustment table gives you a defensible, appraisal-methodology ARV that you can present to lenders, JV partners, or sellers who push back on your offer.

  • Catch bad deals before you make an offer. A LOW confidence score tells you the market is too thin to make a reliable estimate — saving you from over-paying based on weak data.

  • Speed. An analysis that would take a skilled investor or analyst 2–3 hours to complete manually is returned in under 2 minutes.

  • Consistency. The same methodology, the same conservative adjustments, every time — regardless of who on your team runs the analysis.

Who This Is For

  • Fix-and-flip investors making offers that depend on accurate ARV

  • Wholesalers who need to defend their MAO calculation to buyers

  • Lenders and hard money lenders reviewing investment loan applications

  • Acquisition analysts running multiple deal analyses simultaneously

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