What Real Estate Property Taxes Are, How They’re Calculated, and How to Challenge an Assessment

What are real estate property taxes?

Real estate property taxes are local taxes charged on land and buildings. They’re typically billed by a county treasurer or local tax authority and are a major funding source for everyday services you rely on—especially schools, public safety, roads, and community infrastructure.

Unlike income taxes (based on earnings) or sales taxes (based on spending), property taxes are based on the value of what you own: your property’s taxable value and the rates approved by local jurisdictions.

Who sets property taxes (and where the money goes)?

Property taxes are usually a mix of rates from multiple local entities, which can include:

• School districts
• City / township / village governments
• County government
• Libraries, community colleges, and special districts (varies by area)

Your bill may also include special assessments (for example, a neighborhood road project) that are separate from the main property tax rate.

How property taxes are calculated

Most systems follow the same basic structure:

1. Start with value. Your assessor estimates a value for the property. This may be intended to reflect market value, or it may be a percentage of market value based on local law.
2. Apply local rules to get a taxable value. This can include caps, exemptions (homestead, senior, veteran, disability), or classification differences (owner-occupied vs. rental vs. commercial).
3. Multiply by the tax rate. The tax rate may be shown as a percentage or as a millage rate.
4. Add or subtract adjustments. Credits, special assessments, and fees can change the final number.

Common terms you’ll see on an assessment notice

• Market Value: An estimate of what the property could sell for in a normal transaction.
• Assessed Value: The value the assessor assigns for taxation purposes (sometimes tied to market value by a ratio).
• Taxable Value: The figure the tax bill is actually based on after caps/exemptions/rules are applied.
• Tax Rate / Millage: The rate used to convert taxable value into dollars owed.
• Exemptions: Reductions or credits that lower taxable value or the bill itself.

A simplified formula looks like this:

Property Tax Bill = (Taxable Value × Tax Rate) + Special Assessments − Credits

Note: Your “tax rate” might be shown as a percentage (e.g., 2.1%) or as mills (e.g., 21 mills). Both express the same idea.

A simple calculation example

Let’s say your property’s taxable value is $200,000. Your combined local rate is 30 mills.
Since 1 mill = $1 per $1,000 of taxable value:

• $200,000 ÷ $1,000 = 200
• 200 × 30 mills = $6,000

Then special assessments or credits could push the final amount slightly up or down.

Why assessments are often wrong

Assessors are valuing thousands (sometimes hundreds of thousands) of properties. Even with good systems, errors happen.
The most common issues are:

• Bad data: Square footage, bathrooms, basement finish, lot size, or condition recorded incorrectly.
• Wrong comparisons: The model uses “comps” that don’t truly match your home.
• Market shifts: Values can change fast—especially neighborhood by neighborhood.
• Unrecognized defects: Foundation issues, roof problems, water damage, or functional obsolescence.
• Classification or exemption mistakes: Missing exemptions can inflate your bill.

When you should challenge your assessment

An appeal is worth considering if any of these are true:

• Your assessed/taxable value is higher than similar nearby properties.
• You recently purchased the home and the sale price is meaningfully lower than the assessor’s value (timing matters).
• Your property record is wrong (size, features, condition, classification).
• You have major repair issues that reduce market value.
• Your exemption (homestead, senior, veteran, disability, etc.) is missing or misapplied.

How to challenge your property tax assessment (step-by-step)

Step 1: Get the facts from your assessment notice

Pull the notice and write down:

• Market value (if provided)
• Assessed value
• Taxable value
• Tax rate / millage
• Any exemptions listed
• Appeal deadlines and instructions

Step 2: Verify your property record for errors

Look up the assessor’s property record card (often online) and verify:

• Square footage and lot size
• Bedroom/bath count
• Basement / finished space details
• Garage, porch, deck, outbuildings
• Condition notes (and whether they’re accurate)

If something is wrong, document it with photos, measurements, and contractor estimates when relevant.

Step 3: Pull comparable properties (“comps”)

Strong appeals usually lean on comparable sales and comparable assessments:

• Comparable sales: Similar homes that sold around the valuation date (same neighborhood when possible).
• Comparable assessments: Nearby homes similar in size/age/condition that are assessed lower.

Focus on “apples to apples.” A comp that looks close but has a renovated kitchen, extra bath, or finished basement can swing value.

Step 4: Build a one-page “case” with clean math

A simple, effective packet often includes:

• A brief summary: “My value is too high because…”
• 3–6 comps with addresses, sale prices (if available), and notes on differences
• Photos showing condition issues
• Any repair estimates (if defects materially affect value)
• Your requested value (and why it’s reasonable)

Step 5: Start with the easiest path (informal review), then escalate if needed

Many jurisdictions offer an informal review with the assessor before a formal hearing. Typical paths look like:

• Informal review: Quick correction for obvious data errors or clear overvaluation.
• Administrative appeal: A hearing before a local board or review panel.
• Further appeal: State tax tribunal or court (varies by state and property type).

Show up organized, calm, and evidence-driven. Your goal is not to “win an argument,” it’s to show the assessor/review board that the market evidence and property facts support a lower value.

Step 6: Track the result and watch next year’s notice

If you win a reduction, keep the decision letter. If you don’t, your research still helps you verify exemptions and catch errors early next cycle.

FAQ: Property Taxes & Challenging Assessments

What are real estate property taxes?

Real estate property taxes are local taxes charged on land and buildings. They fund services like schools, roads, police/fire protection, and more.

How is my property tax bill calculated?

In most areas, your bill is based on a taxable value multiplied by a local tax rate (often shown as a millage rate), adjusted for exemptions and any special assessments.

What’s the difference between market value, assessed value, and taxable value?

Market value is what the property could sell for. Assessed value is what the assessor assigns for tax purposes. Taxable value is what your bill is actually based on after caps and exemptions.

What is a millage rate?

A millage rate expresses taxes per $1,000 of taxable value. Example: 30 mills means $30 per $1,000 of taxable value.

When should I challenge my property tax assessment?

Consider it if your value is higher than similar properties, if your property record is wrong, or if there are major issues that reduce market value.

What evidence is best for a property tax appeal?

Comparable sales (true “apples to apples”), photos, measurements, repair estimates, and documents showing errors in the assessor’s data.

Can I appeal without a lawyer?

Often yes—especially for informal or administrative appeals. The keys are deadlines, organization, and clear evidence.

How can RealtyPlus help?

RealtyPlus helps you make sense of your assessment, compare it to the market, and decide on practical next steps.
Visit RealtyPlus.com.