The First Principles of Property Tax

Property tax isn't a random number; it is a simple mathematical function of three variables. Regardless of your state, the formula is:

$$Tax = (Market Value \times Assessment Ratio - Exemptions) \times Millage Rate$$

Regional Estimation Guides

Michigan (MI): The "Pop-Up" Tax State

In Michigan, taxes are governed by Proposal A. When a property is sold, the taxable value "pops up" to the State Equalized Value (SEV).

• The Principle: Do not look at the seller's current taxes. They are irrelevant to you.

• Estimation Rule: Take 50% of your purchase price (this is your estimated SEV). Multiply that by the local millage rate (typically 30–55 mills depending on the city).

• Pro Tip: If the home will be your primary residence, ensure you account for the Principal Residence Exemption (PRE), which can reduce your tax bill by roughly 18 mills.

Florida (FL): Save Our Homes (SOH)

Florida rewards long-term residents through the "Save Our Homes" cap, which limits increases in assessed value.

• The Principle: Like Michigan, the previous owner’s tax bill is a "trap." Assessment resets to market value upon transfer.

• Estimation Rule: Estimate taxes at roughly 1.5% to 2% of the purchase price for a safe baseline before exemptions.

• The "Save Our Homes" Benefit: Once you own the home, assessment increases are capped at 3% annually. If you move within FL, you may be able to "port" your tax savings to the new property.

California (CA): The Prop 13 Standard

California has the most predictable first-year tax calculation in the country due to Proposition 13.

• The Principle: Base tax is capped at 1% of the assessed value (purchase price).

• Estimation Rule: Start with 1% of the price, then add "Voter Approved Indebtedness" and Mello-Roos (special assessments common in newer developments).

• Total Target: Budget for 1.2% to 1.25% of the purchase price to account for these local bonds.

Primary Source Government Links

Michigan (MI)

• Official Tool: MI Treasury Property Tax Estimator

  • What to look for: Use this to find the specific Millage Rate for a city or township.

• Educational Resource: Michigan's Property Tax System Guide

  • The Principle: This explains the relationship between SEV (State Equalized Value) and Taxable Value, which is the core of the "Pop-Up" tax.

Florida (FL)

• Official Site: Florida Dept. of Revenue - Property Tax

  • What to look for: Look for the "Save Our Homes" (SOH) assessment limitation and portability details.

• County Level: Florida Property Appraiser Directory

  • The Principle: In Florida, tax rates vary significantly by county; users should use this directory to find their specific County Appraiser's "Tax Estimator" tool.

California (CA)

• Official Site: California Board of Equalization (BOE) - Property Tax

  • What to look for: Read the "Proposition 13" overview to understand how the 1% base rate is applied.

• Local Data: CA County Assessors’ Map

  • The Principle: California buyers must check local assessor sites for Mello-Roos and other special assessments that sit on top of the base 1% tax.

The FPP "Tax Trap" Warning

Regardless of the state, we advise every client to follow the First Principle of Transfer: > Never rely on a seller’s current tax bill. Government sites often provide a "Current Taxes" look-up, but as a new buyer, your taxes will almost always be higher because the sale triggers a "reassessment to market value". Always use the Estimator tools linked above, not the Tax History search.