What gets adjusted
Each sale starts at its closed price. The bedroom gap, bathroom gap, and living-area gap are multiplied by the dollar rates you set. If the subject has more beds than the comp, the comp price goes up, because a buyer of the subject would pay more than that smaller house sold for. The same direction applies to baths and square feet.
Time is a percent of that comp's sale price for each month between the sale date and the as-of date. A positive percent treats the market as rising, so older sales are adjusted up. A negative percent does the opposite. Condition is the step difference on a five-point scale, from poor to renovated, times the dollars per step. The subject condition is the house after rehab, which is why a tired comp usually moves up.
Price per square foot is shown beside each sale so you can see the raw number. It is not the size adjustment. The size adjustment is your own dollar rate times the square-foot difference. Lot size is stored with the subject and is not in the math, because the comps on this page do not carry a lot figure.
Formulas
- Price per sqft = sale price / comp living area. Shown only. A zero or blank living area is left out.
- Bed adjustment = (subject beds − comp beds) × dollars per bed.
- Bath adjustment = (subject baths − comp baths) × dollars per bath.
- Size adjustment = (subject sqft − comp sqft) × dollars per sqft.
- Time adjustment = sale price × (percent per month / 100) × months old.
- Months old = whole calendar months + (day difference / 30.4375).
- Condition adjustment = (subject condition − comp condition) × dollars per step. Condition is clamped to 1–5.
- Adjusted price = sale price + bed + bath + size + time + condition.
- Weight = 1 / (1 + miles) × 1 / (1 + max(months old, 0) / 6). A future sale date counts as zero months in the weight.
- Weighted ARV = Σ (adjusted price × weight) / Σ weight.
- Low and high are the smallest and largest adjusted prices. The simple average is unweighted.
- Max offer at 70% = weighted ARV × 0.70 − rehab budget.
The average, the range, and the 70% link
Weight favors proximity and recency: 1 divided by (1 plus miles), times 1 divided by (1 plus months old divided by 6). The headline ARV is the weighted average of the adjusted prices. The low and the high are the lowest and highest adjusted sales in the set, not a statistical confidence band. A simple average sits next to the weighted one so you can see what the weights did.
The max offer uses the same 70% rule as the flip calculator: weighted ARV times 70% minus the rehab budget. The link opens that calculator with the ARV and the rehab budget in the query string. Purchase price and holding costs stay on the flip example until you change them. This is a screen. It is not an appraisal, and it is not a statement of what a buyer will pay.