Desktop Appraisal Calculator
An adjustment grid — every comparable moved toward the subject line by line, then reconciled by how little moving it needed.
The subject property
3 comparables
Adjustment rates
Contributory values, not costs — a second bathroom does not add what it costs to build. Market-specific; replace with local figures.
Reconciled value
$365,518
$357,385 to $370,988 across 3 comparables
128 Ash$367,610$372,000 sale · −$4,390 net · 34.57% weight
- Living area−$3,150
- Lot size−$1,000
- Age−$2,100
- Market conditions+$1,860
- Net 1.18% · gross 2.18%
45 Poplar$370,988$355,000 sale · +$15,988 net · 33.80% weight
- Living area+$4,050
- Bathrooms+$4,000
- Lot size+$1,400
- Age+$2,100
- Market conditions+$4,438
- Net 4.50% · gross 4.50%
310 Vine$357,385$398,000 sale · −$40,615 net · 31.62% weight
- Living area−$9,000
- Bedrooms−$6,000
- Bathrooms−$4,000
- Garage−$5,000
- Lot size−$3,400
- Age−$4,200
- Condition−$12,000
- Market conditions+$2,985
- Net 10.20% · gross 11.70%
| Reconciled value | $365,518 |
|---|---|
| Unweighted mean | $365,328Shown for contrast — it ignores which comps needed least work |
| Spread | 3.72% |
An estimate from the comparables and adjustment rates you entered. It is not an appraisal, a broker price opinion, or a valuation any lender will accept — a licensed appraiser inspects, verifies the sales, and applies judgement this tool cannot. Use it to form a view before ordering the real thing.
Appraisers adjust. They do not average.
Most free valuation tools take a few nearby sales, divide by square footage, and average. That is a reasonable first pass and it is not what an appraisal is. An appraiser takes each comparable and asks a different question: what would this property have sold for if it had been the subject? Then adjusts it, line by line, until it is.
The grid above does that. Take the default set. 128 Ash sold at $372,000 and is bigger, newer and on a larger lot, so it adjusts down $4,390 to $367,610. 45 Poplar is smaller, older and has half a bathroom less, so it adjusts up $15,988 to $370,988. 310 Vine is superior on almost every line and adjusts down $40,615 to $357,385.
Three sales spanning $43,000 become three opinions of value spanning $13,600. That compression is the whole point of the exercise, and it is what averaging price per square foot cannot do.
Then comes reconciliation, which is where the method differs most from an average. The comps are not equally reliable: 128 Ash needed $8,110 of total adjustment and 310 Vine needed $46,585. One of those is telling you much more about the subject than the other. So each is weighted by how little adjustment it required, and the reconciled figure — $365,518 — sits slightly above the unweighted mean of $365,328, pulled toward the comps that needed least work.
The two guardrails on the grid are the ones appraisers actually use. Net adjustment over 15 percent of sale price, or gross over 25 percent, and the comparable is telling you it is a different property. They catch different problems: a comp that is both much larger and much older can have adjustments that nearly cancel, producing a tiny net and an enormous gross. The net looks fine; the gross says you are stacking guesses. Both are reported per comp, and a breach flags rather than quietly diluting into the average.
The weak point of any grid is the adjustment rates, and it is worth being blunt about it. They are contributory values, not costs — a bathroom that costs $25,000 to build might add $8,000 to value. Appraisers derive them from paired sales analysis in that specific market. The defaults here are placeholders. Get real ones from a local appraiser or an agent who can tell you what the market actually pays for a garage bay in that neighbourhood.
For a fast first pass on a flip, the ARV calculator is the better tool — less data, quicker answer, and it shows its uncertainty as a range. Use this one when you have real comp detail and want something closer to what an appraiser will produce. And if you are trying to work out which kind of appraisal your loan needs at all, see the appraisal types comparison.
Methodology
- Each adjustment moves the comparable toward the subject: where the subject is superior the comp adjusts up, where inferior it adjusts down.
- Physical adjustments = (subject − comp) × the rate, for living area, beds, baths, garage, lot and year built. Condition uses the same form on a 1–5 scale.
- Market conditions = sale price × trend per month × months since sale, adjusting an older sale up in a rising market.
- Net is the sum of adjustments; gross the sum of their absolute values. Adjusted price = sale price + net.
- Weight = sale price ÷ (sale price + gross adjustment). Reconciled value is the weighted mean of the adjusted prices.
Not modelled: location and view adjustments, functional obsolescence, basement finish, pools and outbuildings, sale concessions, distressed or non-arm’s-length sales, and anything requiring an inspection. Those are precisely what an appraiser is for.
Frequently asked questions
- What is a desktop appraisal?
- A valuation performed without visiting the property. The appraiser works from MLS data, public records, tax records and photographs rather than an inspection. Fannie Mae and Freddie Mac accept them on certain low-risk loans, and they are cheaper and faster than a full appraisal — at the cost of never having seen the inside.
- How is this different from the ARV calculator?
- Different method entirely. The ARV calculator normalizes comparables by price per square foot, which is fast and right for a first pass on a flip. This one builds an adjustment grid: each comparable is adjusted line by line toward the subject for size, beds, baths, garage, lot, age, condition and date of sale, then the adjusted prices are reconciled. It is slower, needs more data, and is much closer to what an appraiser actually produces.
- What are adjustment rates and where do I get them?
- They are contributory values — what a difference is worth to a buyer in that market, which is not what it costs to build. A second bathroom might cost $25,000 to add and contribute $8,000 to value. Appraisers derive them from paired sales analysis; short of that, ask a local appraiser or an experienced agent what the market pays for a bedroom or a garage bay in that specific area.
- What do the 15% and 25% guidelines mean?
- Net adjustment over 15 percent of sale price, or gross adjustment over 25 percent, is the conventional signal that a comparable is not really comparable. Net is the sum of the adjustments; gross is the sum of their absolute values, so a comp that is bigger AND older can have a small net and a large gross. Both are reported per comp because they catch different problems.
- Why weight the comps instead of averaging them?
- Because a comparable that needed almost no adjustment is stronger evidence than one that needed heavy adjustment in several directions. An average treats them as equally reliable, which they plainly are not. Each comp here is weighted by sale price over sale price plus gross adjustment, so a comp needing no adjustment carries full weight and one needing adjustment equal to its own price carries half.
- Can I use this for a loan?
- No. No lender will accept a spreadsheet as a valuation, and this is not one. A real appraiser verifies the sales actually closed at those prices and on those terms, checks for concessions, and applies judgement about the local market that no tool has. Use this to form a view before ordering the real thing, or to sanity-check one you have received.
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