A mill is the unit that turns your home's value into a tax bill. Below: how one mill works, who sets it, and how to do the math on your own property.
The short answer
- A mill is a tax rate. One mill = $1 of tax for every $1,000 of taxable value.
- In Georgia, your assessed value is 40% of fair market value (what your home would sell for).
- The millage rate is just how many mills you pay. Taxable value times the rate = your bill.
- In Macon-Bibb, the rate is set by two boards: the Board of Commissioners (county) and the Board of Education (schools).
What this means for you
Your bill is not the millage rate alone. It is also not your home's full sale price. It is built in four steps.
Step 1 — Find the sale price. The county estimates what your home would sell for. That is the fair market value: what a willing buyer and willing seller would agree on in a normal sale.
Step 2 — Take 40%. Georgia law taxes only 40% of that price. That smaller number is your assessed value.
Step 3 — Subtract exemptions. An exemption is a dollar amount that lowers what gets taxed. The most common is the homestead exemption for your primary home. What is left is your net taxable value. (Georgia changed the homestead rules in 2026 — including a duty to tell the county when you stop qualifying, with a penalty for not doing it. Who handles property taxes covers what changed.)
Step 4 — Multiply by the rate. Net taxable value times the millage rate = your tax.
How the math works
Here is the formula, with a real Macon-Bibb example. The thing most people miss: your bill is two millage rates stacked together — the county's rate and your school board's rate — applied to the same value.
The three calculations:
1. Fair market value times 40% = assessed value.
2. Assessed value minus exemptions = net taxable value.
3. Net taxable value times the millage rate = your tax.
A real example, on a $200,000 home in Macon-Bibb:
- $200,000 x 40% = $80,000 (assessed value)
- County: $80,000 x 9.575 mills = about $766
- Schools: $80,000 x 14.674 mills = about $1,174
- Together (about 24.25 mills) = roughly $1,940 a year
Notice the split: the county's 9.575 mills is the smaller slice (about $766), and the Bibb County school board's 14.674 mills is the bigger one (about $1,174). If you own and live in the home as your primary residence on January 1, the homestead exemption (locally $7,000) trims a bit off the top before the rates are applied. The county rate was set August 19, 2025 — the fifth straight annual cut — and both boards set their rates fresh each year in late July or early August, so check the official pages below for the current numbers.
Who does what
Four different offices touch your property tax. They are not the same. Mixing them up is where most confusion starts.
- Board of Commissioners (county): sets the county budget first, then sets the millage rate to cover the part of the budget paid by property tax.
- Board of Education: sets the millage rate for schools.
- Board of Tax Assessors: decides what your home is worth (fair market value). They do not decide your tax.
- Tax Commissioner (currently Wade McCord): sends the bill, collects the money, and passes it on. Does not set the rate.
What the millage rate does NOT do
- It does not decide what your home is worth. The Tax Assessors do that.
- It is not set by the people who collect your bill. The Tax Commissioner bills and collects, but does not set the rate.
- It is not a state tax. Georgia ended its statewide property tax: there has been no state property tax since January 1, 2016. Your property tax is local.
Where to take your question
- Want to know your assessed value? Call the Board of Tax Assessors.
- Question about your bill or a payment? Call the Tax Commissioner's office.
- Think the rate is too high or too low? That is a budget call by the Board of Commissioners (county) and Board of Education (schools).
- Need to call? The Tax Commissioner's office is (478) 621-6500; the Board of Tax Assessors is (478) 200-5550.
Where to go next
- Georgia Dept. of Revenue - Property Tax FAQ — the mill, the 40% rule, and the worked example.
- Macon-Bibb County Tax Commissioner - FAQ — the local definition and the bill formula.
- Macon-Bibb County Tax Commissioner - Property page — who does what.
- Macon-Bibb County Board of Tax Assessors — property value questions.
- Georgia Dept. of Revenue - Property Tax FAQ — supports the mill definition, the 40% assessed-value rule, the fair-market-value definition, and the worked-example method (mill, 40% rule, formula).
- Georgia Dept. of Revenue - Property Tax Millage Rates — supports that Georgia's statewide property tax was phased out to zero (no state levy since January 1, 2016).
- Macon-Bibb County Tax Commissioner - FAQ — supports the one-mill definition, the 40% assessed-value definition, who sets the rate (Board of Commissioners and Board of Education), and the bill formula (subtract exemptions, then multiply by the millage rate).
- Macon-Bibb County Tax Commissioner - Property page — supports the order of budget-then-rate, that the Tax Assessors determine fair market value, and that the Tax Commissioner bills, collects, and distributes property taxes.
- Macon-Bibb County Board of Tax Assessors — supports that the Assessors' job is to appraise property at fair market value.
- Macon-Bibb County — property tax rate cut for the 5th consecutive year — the current 9.575 county millage rate, adopted August 19, 2025.
- 41NBC — Macon-Bibb and Bibb schools 2025 millage rates — the Bibb County school board's 14.674 mills and the combined ~24.25-mill rate used in the worked example.