The sales comparison approach is the method almost every residential valuation in the United States rests on: find properties that recently sold and are genuinely comparable, adjust each sale price for the ways it differs from the subject, and reconcile the adjusted figures into a single indication of value. This page performs that arithmetic on three comparables you choose, using adjustments you determine, and shows you the indication the method returns along with how much adjusting it took to get there.
It is worth being explicit about what this page will not do, because tools with similar names routinely do it. It does not tell you what to offer. There is no recommended bid, no percentage-below-asking rule, and no negotiation strategy anywhere on it. Arb Digital builds calculators that make a published method transparent, and the sales comparison approach is a valuation method, not a bidding method. What you do with a value indication in a negotiation is a decision for you and your agent.
What This Home Offer Price Calculator Does
For each of three comparable sales you enter the sale price, a net adjustment and a gross adjustment, then set the weight you want each comparable to carry. The calculator returns each comparable's adjusted sale price, the weighted indication across all three, the spread between the highest and lowest adjusted figures, and the gross adjustment on each comparable expressed as a percentage of its sale price. The bars compare those gross adjustment percentages, which is a direct read on how comparable your comparables actually are.
The net adjustment is the signed total of every individual adjustment line — positive where the comparable is inferior to the subject and needs adding to, negative where it is superior. The gross adjustment is the sum of those same lines taken as absolute values. Two comparables can carry an identical net adjustment of zero, one because nothing needed adjusting and one because a large positive and a large negative happened to cancel. The gross figure is what separates them, and it is the single most useful diagnostic on this page.
How to Use It
- Choose comparables before you choose numbers. Same market area, same property type, recent closings. A comparable that needs heroic adjustment was not comparable to begin with.
- Build each net adjustment line by line. Gross living area, lot size, condition, age, garage, bathrooms, location, and sale concessions each get their own line, and each should be supported by something you can point at rather than a rule of thumb.
- Total the absolute values for the gross figure. If the gross adjustment on a comparable exceeds a modest share of its sale price, treat its indication with caution regardless of where the net lands.
- Set the weights deliberately. The comparable that needed the least adjustment is normally the one that deserves the most weight, and you should be able to say why in a sentence.
- Read the spread, not just the indication. A tight spread means three independent routes agreed. A wide one means the method has not converged and the answer is a range, not a number.
The Formula / How It's Calculated
Each comparable's adjusted sale price = sale price + net adjustment. The weighted indication = Σ(adjusted price × weight) ÷ Σ(weights), so the weights normalise themselves and need not sum to 100. The spread is the highest adjusted price minus the lowest. The gross adjustment percentage for each comparable is gross adjustment ÷ sale price × 100.
Worked through the values the page loads with: comparable 1 sold at $615,000 with a net adjustment of −$18,000, giving an adjusted price of $597,000. Comparable 2 sold at $585,000 with a net adjustment of +$12,500, giving $597,500. Comparable 3 sold at $640,000 with a net adjustment of −$35,000, giving $605,000. Weighted 50 / 30 / 20 the indication is (597,000 × 50 + 597,500 × 30 + 605,000 × 20) ÷ 100 = $598,750, with a spread of $8,000 between the highest and lowest. The gross adjustments come out at 6.83%, 5.30% and 9.06% of their respective sale prices, which is why comparable 3 carries the lowest weight in the example.
Where the Adjustments Have to Come From
The arithmetic above is trivial. Every difficult part of the sales comparison approach lives in the adjustment figures, and that is exactly the part a calculator cannot supply. Fannie Mae's selling guide section on adjustments to comparable sales is explicit that adjustments must reflect actual buyer reactions in the market rather than arbitrary limits or rules of thumb, and that an appraiser must provide fact-based, objective commentary detailing the work performed to support each one.
The same guidance makes two further points worth carrying into any use of this page. Sales or financing concessions on a comparable — interest rate buydowns, closing costs, loan fees — require adjustment, because a sale price that includes a concession reflects more than the value of the real estate. And where time has passed between a comparable's contract date and the valuation date, a market conditions adjustment may be warranted, supported by evidence such as a house price index rather than by assertion. If your comparables closed six months ago in a moving market, that adjustment is not optional.
Why a Licensed Professional Still Values the Property
An indication produced from three comparables and a set of adjustments you selected is exactly as good as those selections. A licensed appraiser does the same arithmetic but brings the things that determine whether it means anything: access to full sale records rather than public listings, knowledge of which sales were arm's length, the ability to inspect the subject and the comparables, and market-derived support for each adjustment. The Consumer Financial Protection Bureau describes what an appraisal is and why you should read it — a written document giving an opinion of how much a property is worth, describing what makes it valuable and how it compares to similar homes in the area — and notes that on a first-lien mortgage you are entitled to a free copy of it.
Three specific things will move a number produced here and none of them are visible in the arithmetic. The market moves, sometimes quickly, and an indication built on spring closings can be stale by autumn. A survey can reveal an encroachment, an easement or a boundary that is not where anyone thought it was. An inspection can find a roof, a foundation or a system that changes the condition adjustment by more than every other line combined. A licensed appraiser or a local agent values a specific property; this page performs arithmetic on figures you supply.
How This Differs From Our Home Value Tool
Our home value estimate calculator works from characteristics of the property itself to produce a value estimate, and it is the right starting point when you do not yet have comparables in hand. This page runs the sales comparison method explicitly: it needs three actual sales, three actual adjustment totals, and your judgement about weighting, and in exchange it shows the full working and the diagnostics. One is an estimate of value; the other is a transparent reconstruction of how a valuation professional reaches one.
Neither is a bid. If you are working towards a purchase, the value indication is one input among several, and the constraints usually bind elsewhere: our house affordability calculator covers what a household can carry, the mortgage calculator covers the payment, the down payment calculator the cash at risk, and the closing cost calculator the money that never appears in the price.
Reading the Spread and the Gross Adjustments Together
The two diagnostics on this page are more informative together than separately. A tight spread with low gross adjustments means three genuinely similar properties independently pointed at the same value, and that is the strongest result the method can give. A tight spread with high gross adjustments is weaker than it looks: the agreement may be an artefact of adjustment choices that all leaned the same way, which is a real risk when one person derives all three sets of adjustments.
A wide spread with low gross adjustments is the most interesting case, because it usually means the market itself is dispersed — thin trading, unusual properties, or a segment where buyers genuinely disagree. The honest output there is a range rather than a point, and reporting a single weighted figure would give false precision. A wide spread with high gross adjustments generally means the comparables are not comparable, and the answer is to find better sales rather than to reweight the ones you have. On the sale side of the same transaction, our home sale proceeds calculator and cost per square foot calculator handle the related arithmetic.
Arb Digital designs and maintains calculator libraries that earn organic search traffic, with every method sourced to a named authority and every formula worked through in public.
Browse All Free Tools Talk To Arb DigitalCommon Mistakes to Avoid
- Using rules of thumb as adjustments. Published guidance requires adjustments to reflect actual market reactions supported by evidence, not a fixed dollar figure per bedroom carried in from somewhere else.
- Ignoring sale concessions on the comparables. A price that includes a buydown or paid closing costs reflects more than the real estate, and leaving it unadjusted contaminates every figure built on it.
- Skipping the market conditions adjustment. Comparables that closed months ago in a moving market need a time adjustment supported by an index, not an assumption that nothing changed.
- Reading a tight spread as confirmation. Three comparables adjusted by one person can agree because the adjustments leaned the same way, which is why the gross adjustment percentages matter.
- Treating the indication as an offer. It is a value indication from a published method. What to offer depends on the market, the survey, the inspection and your own position, and is a conversation with a licensed agent.
Related Free Tools From Arb Digital
Start with the home value estimate calculator if you do not yet have comparables, and use the cost per square foot calculator to sanity-check area-based adjustments. On the purchase side, the house affordability calculator, mortgage calculator, down payment calculator and closing cost calculator cover the money, and the home sale proceeds calculator covers the other side of the table. Browse the full free online tools hub for the rest.
Frequently Asked Questions
No. It returns the value indication that the sales comparison method produces from the comparables and adjustments you entered. It contains no bidding rule and recommends no offer. What to offer depends on the market, the survey, the inspection and your own circumstances, and is a discussion with a licensed agent.
It is the standard residential valuation method: take recent sales of genuinely comparable properties, adjust each sale price for the ways that property differs from the subject, and reconcile the adjusted figures into a single indication of value.
The net adjustment is the signed total of every adjustment line. The gross adjustment is the sum of the same lines taken as absolute values. Two comparables can share a net of zero while one needed no adjustment at all and the other needed large offsetting ones, and only the gross figure reveals the difference.
Appraisal practice gives the most weight to the comparable requiring the least adjustment, and requires the reconciliation to explain why. The weights on this page are yours to set and are normalised automatically, so they need not sum to one hundred.
Yes. Published guidance treats sales and financing concessions as requiring adjustment, because a sale price that includes a buydown, paid closing costs or loan fees reflects more than the value of the real estate itself.
Because an appraiser has full sale records rather than public listings, can verify which sales were arm's length, inspects the properties, and derives each adjustment from market evidence. The arithmetic is the same; the inputs are better.
The market, which moves and can make recent closings stale. The survey, which can reveal easements or boundaries nobody expected. And the inspection, which can shift the condition adjustment by more than every other line put together.
This page performs the arithmetic of a published valuation method on figures you supply and is not an appraisal, a valuation, or advice on what to pay for any property. A licensed appraiser or real estate agent values a specific property; consult one before acting on any figure here.
