Property Adjustment Calculator
Adjust comparable sales to estimate subject property value. Enter subject and comp characteristics, then review net/gross adjustments and the indicated value range.
Adjust the COMP to the SUBJECT, not the other way around
Add for inferior comp features, subtract for superior
Net adjustments should not exceed 10-15% of sale price
Gross adjustments should not exceed 25% of sale price
Subject Property
Comparable Sales
1Comp 1
Adjustments ($)
2Comp 2
Adjustments ($)
3Comp 3
Adjustments ($)
Sales Comparison Approach Guide
How Adjustments Work
The sales comparison approach estimates value by comparing the subject property to recently sold similar properties (comparables). Adjustments are applied to each comparable to account for differences. If a comp is superior to the subject in some way, you subtract from its price. If the comp is inferior, you add to its price. This estimates what the comp would have sold for if it were identical to the subject.
Adjustment Thresholds
As a rule of thumb, net adjustments should generally not exceed 10-15% of the comparable's sale price, and gross adjustments should not exceed 25%. When adjustments are excessive, it suggests the comparable may not be sufficiently similar to the subject. Large adjustments reduce the reliability of the indicated value and may require additional explanation in the appraisal report.
Reconciliation
After adjusting all comparables, the appraiser reconciles the adjusted prices to arrive at a single opinion of value. This is not a simple average — the appraiser gives more weight to comparables that required fewer adjustments, had the most reliable data, and were most similar to the subject overall. The indicated value should fall within the range of adjusted comparable prices. This calculator shows the median as a starting point, but professional judgment should always guide the final value conclusion.
Understanding Sales Comparison Adjustments
The sales comparison approach is the most widely used appraisal method for residential properties. Its accuracy depends entirely on the quality and consistency of the adjustments an appraiser makes. Below is a deeper look at the principles that govern these adjustments.
When to Add vs. Subtract Adjustments
The cardinal rule is simple: always adjust the comparable, never the subject. Think of each adjustment as answering the question, “What would this comparable have sold for if it were identical to the subject?”
- Comparable is superior (better than subject): Subtract from the comparable’s sale price. The comp sold for more because of its superior feature, so you reduce it to match the subject.
- Comparable is inferior (worse than subject): Add to the comparable’s sale price. The comp sold for less because it lacked something the subject has, so you increase it.
A popular exam mnemonic is “CBS” — Comp Better, Subtract. If you remember this rule, you will get adjustment-direction questions right every time.
Net vs. Gross Adjustment Guidelines
Lenders and review appraisers use two metrics to gauge the reliability of a comparable:
- Net Adjustment — The algebraic sum of all positive and negative adjustments. Positive and negative adjustments can offset each other. Rule of thumb: net adjustments should not exceed 10-15% of the comparable’s sale price.
- Gross Adjustment — The sum of the absolute values of all adjustments (ignoring sign). This measures total magnitude of change. Rule of thumb: gross adjustments should not exceed 25% of the comparable’s sale price.
When either threshold is exceeded, it signals that the comparable may not be sufficiently similar to the subject. On the appraiser exam, you may be asked to identify which comparable is the “best” indicator of value — the answer is almost always the one with the lowest gross adjustment percentage.
Paired Sales Analysis
To determine the dollar amount of an adjustment, appraisers use paired sales analysis. This technique compares two sales that are identical in every respect except one feature. The difference in sale prices isolates the value contribution of that feature. For example, if Sale A (with a garage) sold for $310,000 and Sale B (identical but without a garage) sold for $285,000, the indicated adjustment for a garage is $25,000. On the exam, paired sales analysis problems are common and straightforward once you understand the concept.
Sequence of Adjustments
Adjustments are typically applied in a specific order: (1) property rights conveyed, (2) financing terms, (3) conditions of sale, (4) market conditions (time), and then (5) physical characteristic adjustments (location, size, quality, condition, etc.). The first four are applied sequentially (multiplicatively), while physical adjustments are applied additively to the time-adjusted sale price.
Frequently Asked Questions
Master Appraisal Concepts
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