Desktop Appraisal Calculator
What would an appraiser put this at? Value a property from adjusted comps the way an appraiser reconciles them.
Reconciled value
$314,746
The subject property
Every adjustment below is the subject measured against a comp, so this is the baseline.
Above-grade only. Basements are not living area.
An acre is 43,560 sq ft
Half baths count as 0.5
Adjustment rates
What one unit of each difference is worth in your market. These are contributory value, not replacement cost — a bathroom almost never adds to a sale what it costs to build.
Well below the market's rate per foot — you are pricing the difference, not the house
Usually a small fraction of the living-area rate
Negative in a falling market. Drives the date-of-sale line.
An appraiser normally drops a comp adjusted that far, and explains why.
Comparable sales
Closed sales only. A comp needs both a sale price and a living area to be used.
Positive if the subject is in better shape than this comp
Positive if the subject is in better shape than this comp
Positive if the subject is in better shape than this comp
Reconciled value
$314,746
Weighted from 3 adjusted comps bracketing $311,774 to $319,022.
- Bracket low
- $311,774
- Bracket high
- $319,022
Comps reconcile tightly
3 adjusted sales inside 2.3% of each other, all within the 25% gross and 15% net guidelines. That is a supportable value, and the weighting barely matters when the comps already agree.
What the reconciled value is made of
- Comp A — 1.8% gross43%
- Comp B — 8.8% gross30%
- Comp C — 10.9% gross26%
Reconciliation
- Comp A — adjusted1.8% gross adjustment, weighted 43%
- $311,774
- Comp B — adjusted8.8% gross adjustment, weighted 30%
- $315,269
- Comp C — adjusted10.9% gross adjustment, weighted 26%
- $319,022
- Reconciled value
- $314,746
- Adjusted price bracketThe reconciled value must sit inside this, and does by construction
- $311,774 – $319,022
- Implied rate per square footSanity check against what the raw comps sold for per foot
- $186.79
The adjustment grid
Each comp’s sale price, adjusted for every way it differs from the subject. A positive line means the subject is superior and the comp’s price is being raised toward it.
| Line | Comp A | Comp B | Comp C |
|---|---|---|---|
| Sale price | $312,500 | $289,900 | $334,000 |
| Living area | −$2,530 | +$3,450 | −$9,200 |
| Bedrooms | — | — | −$5,750 |
| Bathrooms | — | +$4,125 | −$4,125 |
| Garage spaces | — | +$4,800 | — |
| Lot size | −$696 | +$696 | −$2,091 |
| Condition | — | +$6,500 | −$4,500 |
| Date of sale | +$2,500 | +$5,798 | +$10,688 |
| Net adjustment | −$7260.2% | +$25,3698.8% | −$14,9784.5% |
| Gross adjustment | 1.8% | 8.8% | 10.9% |
| Adjusted price | $311,774 | $315,269 | $319,022 |
| Weight | 43% | 30% | 26% |
Figures in clay are past a guideline: a single line worth more than 10% of the comp’s sale price, a net adjustment past 15%, or gross adjustments past 25% — the point at which an appraiser normally drops the comp rather than explaining it.
If your square-foot rate were different
The living-area rate is the most arbitrary number on the page and the one with the most leverage. Each row re-runs the whole grid — the adjustments, the weights and the reconciliation.
| Per sq ft | Reconciled | vs. yours |
|---|---|---|
| $36.00 | $315,334 | +$588 |
| $41.00 | $315,037 | +$291 |
| $46.00yours | $314,746 | — |
| $51.00 | $314,459 | −$287 |
| $56.00 | $314,177 | −$569 |
How this is calculated
The sales comparison approach adjusts the comp toward the subject, never the other way round. For each comparable sale:
adjusted price = sale price + Σ (subject − comp) × rate + condition + time
Each physical line is the difference in units multiplied by what one unit is worth: (subject sq ft − comp sq ft) × rate per sq ft, and the same shape for bedrooms, bathrooms, garage spaces and lot area. A positive line means the subject is superior, so the comp’s price is raised toward it. Condition is entered as dollars rather than derived, because there is no unit to count. The date-of-sale line is sale price × market movement per month × months since it closed— proportional to the comp’s own price rather than a flat figure, because a market moving half a point a month is worth more on an expensive house than a cheap one.
A line is priced only when both sides of the difference were given. Leave the subject’s lot size blank, or a comp’s bedroom count, and that line is marked not givenand contributes nothing, rather than being read as a lot of zero square feet and adjusted by the whole of the other side. Nothing at all can be computed without the subject’s living area and each comp’s sale price and living area, because the size line is normally the largest on the grid.
Two ratios then measure how hard each comp had to be worked. gross = Σ |adjustment| ÷ sale price is the total distance the comp travelled; net = Σ adjustment ÷ sale price is how far it ended up from where it started. The pair matters because they say different things: a comp with large adjustments that cancel is different from the subject in offsetting ways, which is normal, while a comp whose adjustments all pull the same way is systematically different — and if your rates are slightly wrong, the error compounds instead of cancelling.
Reconciliation weights each comp by the headroom it has left against the 25% gross guideline: weight = 25% − gross, floored just above zero, and the reconciled value is the weighted mean of the adjusted prices. The obvious alternative, one over the gross adjustment, is far too aggressive — a comp at 2% against comps at 9% and 11% takes about three quarters of the answer, which is a single-comp valuation wearing a reconciliation’s clothes. This weighting is linear, ties directly to the guideline the grid is already measured against, and gives a comp sitting at the limit essentially no say.
Comps past the gross guideline are left out of the reconciliation by default and named, because at that point a comp has been adjusted into agreement rather than found in agreement. The bracket shown alongside the value is the lowest and highest adjusted price among the comps that were kept: adjusting should pull comps together, and when a bracket stays wide after adjustment the difference is something the grid has no line for — a view, a busy road, a school boundary, a flood zone.
The sensitivity table re-runs the entire grid at four other square-foot rates. It has to re-run all of it rather than moving one line, because changing the rate changes each comp’s gross adjustment, which changes its weight, which changes the reconciled value by more than the size line alone would suggest.
Common questions
What is a desktop appraisal?
It is a valuation performed from records rather than from a visit — the appraiser never walks the property and works from tax records, listing data and photographs. Lenders use them where the loan is small relative to the value and the property is ordinary. This calculator reproduces the arithmetic of the sales comparison approach that sits at the centre of one, but it is not a desktop appraisal: nobody signs it, no licence stands behind it, and it uses the characteristics you type rather than public record.
How do I choose the adjustment rates?
They are contributory value, not cost. What matters is what a buyer in that market pays for one more bedroom, not what a bedroom costs to build — and the two are rarely close. The most defensible way to derive them is paired sales: find two sales alike in everything except the feature and take the difference. Failing that, start conservative. The square-foot rate is usually a long way below the market's headline rate per foot, because you are pricing the marginal foot in an otherwise similar house, not the whole house.
Why is the biggest comp not always the most important one?
Because the reconciliation weights by how little a comp needed adjusting, not by size, price or recency. A comp two blocks away that matches the subject in every respect needs almost no adjustment, so almost none of the answer is your opinion — it is the market's. A comp needing a large size adjustment plus a garage adjustment plus a condition adjustment produces an adjusted price built mostly from your rate assumptions, and it deserves less weight for exactly that reason.
What do the 25% and 15% figures mean?
They are the long-standing underwriting guidelines for adjustments: no more than 25% of the comp's sale price in gross adjustments (the absolute values added together), no more than 15% net (after they offset each other), and no single line past 10%. A comp beyond the gross figure has been adjusted into agreement rather than found in agreement, and an appraiser normally drops it or writes an explanation. This tool leaves those comps out of the reconciliation by default and tells you which ones went.
Why does the date of sale need an adjustment?
Because a comp is evidence of what the market paid on the day it closed, not today. In a market moving half a point a month, a sale eight months old understates today's value by about four percent before anything else is considered, and that is larger than most of the physical adjustments on the grid. Enter a negative rate in a falling market and the adjustment reverses on its own. The honest way to set the rate is from a local price index, not from a feeling about the market.
Should I use this or the ARV calculator?
Use the ARV calculator to screen: it collapses the comps into one rate per square foot and gives you a range in under a minute, which is the right amount of work for a property you may not buy. Use this one when the deal is real and the comps differ from the subject in ways a rate per foot cannot see — a different bathroom count, no garage, a much larger lot, a sale from last year. It is more work and the answer carries an audit trail, which is what you need when you are arguing about the number with a lender or a seller.
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Browse off-market dealsThis calculator estimates results from the numbers you enter. It does not know the property, your lender’s terms, local taxes or the rules of your state, and it is not financial, tax or legal advice. Nothing here has been reviewed by a lawyer. Confirm every figure with your lender, title company and your own professionals before you rely on it.