Tool
Before and after value calculator
Compensation in a partial taking is the before value less the after value. This applies that subtraction, separates severance damages from the land itself and compares the result with the proportional calculation an offer is sometimes based on.
Enter the two values
Everything below the first two fields is optional.
Enter a before value and an after value to see the result.
How to use it
Where the numbers come from
The before and after values are opinions, and the calculator cannot produce them. They come from an appraisal: yours, the agency\u2019s, or both. What the calculator does is show what those two opinions imply, and in particular how much of the compensation is damage to the remainder rather than payment for the land taken.
That separation is useful because it is the part most often disputed. An agency offer built on a price per square foot, multiplied by the area taken, is the proportional calculation this tool compares against. Where the taking damaged the remainder, that method understates compensation by the whole of the damage.
If you have only the agency figures, enter those. The result tells you what the agency appraisal implies about severance damages, which is often nothing. That is itself the finding worth pursuing.
Questions about the calculation
Can I use this to decide whether to accept an offer
No. It performs arithmetic on figures you supply. Whether those figures are right is the entire question, and answering it requires an appraisal.
What if the agency has not given me an after value
Many agency appraisals do not state one clearly, which is itself informative. Ask for it. If the report contains no separate analysis of the remainder, the after value has been assumed rather than determined.
Why does the proportional comparison matter
Because a proportional offer, the area taken as a fraction of the whole, is a common starting point and it captures only the land. It cannot show damage to the remainder, by construction.
The numbers are the easy part
Producing a defensible before value and after value is the work. If the figures you have came from an appraisal you did not commission, having it reviewed is the usual next step.