Know before you go
- Georgia assesses homes at 40 percent of fair market value; one mill is $1 per $1,000 of that value.
- Before exemptions, a $400,000 home owes about $4,821 in unincorporated Cobb and $7,054 in unincorporated DeKalb in 2026.
- Fulton County’s 2026 bills are temporary, figured on 2025 millage rates under a court order.
The formula
Every Georgia property tax bill follows the same arithmetic. The county board of tax assessors sets a fair market value. By law, homes are assessed at 40 percent of that value. Exemptions are subtracted from the assessed value, and the rest is multiplied by the millage rate, where one mill is $1 of tax for every $1,000 of assessed value. The millage rate is the sum of the rates set by the county, the school district, the city if there is one, and any special districts.
So a $400,000 home has an assessed value of $160,000. At 30 mills, the bill before exemptions is $4,800; at 45 mills it is $7,200. The rate, not the formula, is what differs from one address to the next.
2026 rates, district by district
These totals come from the 2026 rate sheets published by each county’s tax commissioner. They include county, school and city levies but leave out community improvement district levies, which are added only inside those districts.
| County and tax district | 2026 total mills | Bill on $400,000 before exemptions |
|---|---|---|
| Cobb, unincorporated | 30.13 | $4,821 |
| Cobb, Marietta (county + city) | 31.122 | $4,980 |
| Cobb, Smyrna | 36.15 | $5,784 |
| Cobb, Kennesaw | 39.28 | $6,285 |
| Gwinnett, unincorporated | 34.86 | $5,578 |
| DeKalb, Dunwoody | 40.199 | $6,432 |
| DeKalb, Brookhaven | 41.469 | $6,635 |
| DeKalb, unincorporated | 44.090 | $7,054 |
| DeKalb, Decatur | 44.695 | $7,151 |
| DeKalb, Tucker | 45.791 | $7,327 |
The spread is wide: the same $400,000 house could carry a bill around $2,500 higher in some DeKalb districts than in unincorporated Cobb, before exemptions. Exemptions differ by county too, so the real gap for an owner-occupant depends on where you apply. The school levy is the largest single piece almost everywhere: 18.70 mills for the Cobb County School District, 18.7 plus 1.45 for bonds in Gwinnett, and 22.780 for the DeKalb County School District.
Fulton County in 2026: temporary bills
Fulton County’s 2026 bills work differently this year. The county says submission of the 2026 tax digest to the Georgia Department of Revenue was delayed, and the digest has to be certified before taxing authorities can set their millage rates. On August 4, 2026, the Superior Court of Fulton County authorized temporary bills based on the preliminary 2026 digest and each jurisdiction’s 2025 millage rate. City of Atlanta taxes were due September 30, 2026, and Fulton County and other jurisdictions’ taxes October 15, 2026. Once final rates are set, the county says, a refund or revised bill will be issued only as needed.
For reference, the Fulton County general fund rate was 8.87 mills in 2025, unchanged since 2022, and Atlanta Public Schools has kept its rate at 20.5 mills since 2022. City and other school rates are set separately.
Tip: If you buy in Fulton County this year, ask the closing attorney how the temporary 2026 bill is being prorated, since a revised bill could follow.
The yearly cycle
- January 1: ownership and use on this date decide who owes the tax and who can claim a homestead exemption.
- January 1 to April 1: the window to file property tax returns and homestead applications.
- Each year: the county board of tax assessors mails an annual notice of assessment; bills also show fair market value and assessed value.
- 45 days from the notice: the period to appeal the value in writing.
- After the digest: millage rates are adopted and bills go out. Gwinnett’s 2026 bills, for example, are due November 15.
If you think the value is wrong
The Department of Revenue explains that the county board of tax assessors sends an annual notice of assessment with information on filing an appeal. An owner who disagrees can appeal to the county board of equalization, a hearing officer or arbitration, under O.C.G.A. 48-5-311. The appeal is filed with the board of tax assessors within the 45-day window. Recent sales of similar homes nearby are the usual evidence.
Paying late costs more
Fulton County’s 2026 notice spells out the penalty schedule: interest starts the day after the due date, and an additional 5 percent penalty is charged on the 120th day and every 120 days after that, up to a maximum of 20 percent. If you pay through a mortgage escrow account, the lender pays the bill, but it is still worth checking that it did.
Lowering the bill legally
The main tool is the homestead exemption: Cobb’s basic $10,000 exemption saves $271.60 a year on county and school taxes, and Fulton’s $30,000 county exemption saves about $266 at the 2025 rate, with floating exemptions limiting how fast taxable value can rise. Seniors and some veterans qualify for more. The details are in The Georgia Homestead Exemption for Atlanta-Area Buyers: Who Qualifies and How It Floats, and how taxes fit into the decision to buy is in Rent vs Buy in Metro Atlanta: What the Census Numbers and Georgia Rules Say.