Modeling Florida's Amendment 3 property tax exemption, county by county, in Python

Florida votes on Amendment 3 on November 3, 2026. The ballot summary is one sentence long, but the question every homeowner actually has — what does this do to my bill? — depends on two numbers that differ by county: the school millage and everything else. So I modeled it for all 67 counties.

The rule, in code

Florida bills split into two kinds of millage (dollars of tax per $1,000 of assessed value): school and non-school (county, city, special districts). Today a homestead gets two exemptions:

• $25,000 off the assessed value for all taxes;
• a second exemption, up to $25,722 for 2025 (indexed to inflation), on value between $50,000 and $75,000 — non-school taxes only.

Amendment 3 replaces both. Per the Property Appraisers' Association of Florida's FAQ, a homestead would get $25,000 off for school taxes (unchanged) and up to $150,000 in 2027, then $250,000 in 2028 off for non-school taxes, indexed from 2029.

def current_tax(value, school_mills, other_mills):
    first = min(value, 25_000)
    second = min(max(value - 50_000, 0), 25_722)
    return ((value - first) * school_mills
            + (value - first - second) * other_mills) / 1000

def amendment3_tax(value, school_mills, other_mills, non_school_exempt):
    school_taxable = value - min(value, 25_000)
    other_taxable = value - min(value, non_school_exempt)
    return (school_taxable * school_mills + other_taxable * other_mills) / 1000

Two things fall straight out of the code:

1. Savings are capped. Once the home is assessed at $250,000 or more, the extra exemption is fixed at about $199,278 of value ($250,000 minus today's $50,722). In dollars it can't exceed 199.278 × non-school mills, so it is the same for a $300,000 home and a $3 million one.
2. School taxes become most of the bill. In the median county, school millage makes up about 87% of what a median-value homestead would still owe in 2028.

The data

The Florida Department of Revenue publishes each county's 2025 millage: school operating, school debt, county, municipal and special district averages. Splitting school from everything else:

import pandas as pd

fl = pd.read_csv("florida_millage_2025.csv")
fl["school"] = fl["school_operating"] + fl["school_debt"]
fl["other"] = fl["total_mills"] - fl["school"]

For a "typical" home I used the Census ACS median value of owner-occupied homes in each county. That's a market value, not an assessed value, which matters (see below).

What it shows

At 2025 millage, for a homestead at the county's median home value:

County	Median value	Tax now	2027	2028	Saves (2028)
Miami-Dade	$463,000	$7,793	$6,616	$5,431	$2,363
Broward	$414,600	$7,395	$6,067	$4,729	$2,666
Palm Beach	$447,300	$7,099	$5,990	$4,873	$2,226
Hillsborough	$371,500	$6,211	$4,969	$3,717	$2,494
Orange	$390,100	$6,074	$4,986	$3,890	$2,184

Across all 67 counties:

• The median county saves about $1,559 a year in 2028, and $949 in 2027.
• In percent, cuts range from 17% to 67% of the bill (median 53%). The biggest percentage cuts are in cheaper counties; the biggest dollar savings are where non-school millage is high and homes are worth more than $250,000 (St. Lucie, about $3,041; Alachua, about $2,917).
• In 9 counties the median home is worth less than $150,000, so the 2027 exemption already covers it and the bill drops to school taxes only.

What the model leaves out

This is the part I'd want a reader to take seriously:

• Assessed value isn't market value. Save Our Homes caps a homestead's assessed value growth at 3% a year (or CPI). Someone who has owned since 2010 may be assessed at half the market value, so their dollar savings are smaller. The ACS medians overstate assessed value for long-time owners.
• Rates aren't fixed. The amendment changes taxable value, not millage. Because the taxable base shrinks, the "rolled-back rate" on 2027 TRIM notices effectively becomes a rolled-up rate, and each county, city and district sets its own millage in its budget. Holding 2025 rates constant is a lower bound on what local governments would need to change.
• New residents wait. People who become Florida residents on or after January 1, 2027 start with a $50,000 non-school exemption and get the larger one from their fifth year.
• County averages. The millage is a county-wide average including cities; a home in an unincorporated area or in a specific city will differ.

Try it

I put the model into a calculator with a county picker and the full 67-county table (sortable), so you can plug in the assessed value from your own TRIM notice: https://countypropertytaxes.com/florida-amendment-3-calculator/

The underlying CSVs (Florida millage, plus Texas and North Carolina rates and Census medians for every county) are CC BY 4.0 on Kaggle, Hugging Face and Zenodo if you want to run your own version.