An assessment is an estimate, not a bill
A property assessment is a value assigned by a local assessing authority for property-tax purposes. It is commonly based on property records and valuation methods applied to many homes, rather than a custom inspection of every detail inside each home.
The assessed value is one input in the tax calculation. The amount due can also depend on the local tax rate, exemptions, credits, caps, and other rules. Those details differ by location, so a change in assessed value does not translate into the same change in tax for every homeowner.
Assessed value and sale price are not always the same
A recent sale can be useful evidence of market value, but an assessment may use a different valuation date, a mass-appraisal method, or a locally defined percentage of value. The property record may also be missing an update or may describe features differently from the home as it exists today.
For that reason, compare the notice with the authority's stated valuation date and method before drawing conclusions. A current online estimate or a neighbor's assessment is not, on its own, proof that your value is wrong.
What to review on the notice
Check the property address, lot size, building area, age, condition, major improvements, and any other characteristics listed. Look for clear factual errors first: a finished area that does not exist, an improvement credited to the wrong property, or a condition description that does not match the home.
Keep the notice and its envelope or electronic delivery record, and find the local assessor's instructions and dates. If something appears incorrect, ask the assessing office how to correct the record and what review options are available where you live.