Key takeaways
- Confirm the client's filing frequency on the Georgia Tax Center before building the calendar.
- The December 2026 monthly return, the 4th Quarter 2026 return and the 2026 Annual Return are all due 1/20/2027.
- A client who owes more than $500.00 on a return must file and pay electronically.
- On a return with $500.00 of tax, each late month adds $25, and the late-return line stops at 25% of the tax.
- Each local tax row has its own effective and end dates, so check the row that covers the sale date.
What the ST-3 is and which version to use
The paper Georgia sales and use tax return is Form ST-3. The Department of Revenue lists ST-3 versions by the period of sales each one covers, and it lists two addendums separately: ST-3 Addendum Sales and ST-3 Addendum Use.
Match the ST-3 version to the sales period before you fill it in. A return for 2026 sales should use the version the DOR lists for those sales dates, not a form copied from last year's client folder.
Do not attach an addendum by default. Check the sales and use activity for the period first, then file each addendum that covers activity the client actually had.
Set the filing frequency before the calendar
The DOR's due-date page is organized as monthly, quarterly or annual periods. A monthly filer has twelve 2026 due dates, a quarterly filer has four, and an annual filer has one, the 2026 Annual Return.
Frequency is set on the state account, not in the firm's calendar. Write the frequency the DOR has on file for the client into the client record before building the calendar, and rebuild the calendar if the two disagree.
The 2026 due dates, copied from the DOR table
The DOR table pairs each monthly period with the 20th of the following month. When the 20th falls on a weekend, the table shows the next business day. The May 2026 period is due 6/22/2026 because June 20, 2026 is a Saturday, and the November 2026 period is due 12/21/2026 because December 20, 2026 is a Sunday.
The 2026 entries are: January period 2/20/2026; March period 4/20/2026; 1st Quarter 2026 4/20/2026; August period 9/21/2026; September period 10/20/2026; 3rd Quarter 2026 10/20/2026; October period 11/20/2026; November period 12/21/2026; December period and 4th Quarter 2026 1/20/2027; 2026 Annual Return 1/20/2027.
Copy the table date exactly. A bookkeeper who calculates the 20th alone will put 12/20/2026 on the calendar for the November period, which is a Sunday and not the date the DOR published.
Local layers: LOST, SPLOST, TSPLOST and the rest
The DOR's local sales and use tax history chart, effective April 1, 2026, lists local tax types by jurisdiction. The types on the chart are ELOST, LOST, SPLOST, TSPLOST and PTRLOST, and each row carries its own effective and end dates.
A row stops applying after its end date. The April 1, 2026 chart lists a Bacon SPLOST row effective 04/01/2024 and ending 03/31/2030. A sale after a row's end date needs a different row, or none, and the rate on that sale changes.
For each sale, find the jurisdiction the sale is sourced to under the client's sourcing rule, then match the tax-type rows that cover the sale date. Do not reuse last quarter's local rate without checking the end dates on the chart.
Electronic filing: the $500.00 rule and the EFT rule
The DOR says a taxpayer that owes more than $500.00 is required to file and pay electronically through the Georgia Tax Center. It also says a taxpayer that remits by electronic funds transfer must file all associated returns electronically, whether the EFT is mandatory or voluntary.
Decision rule: if the client owed more than $500.00 on any return, or pays by EFT, file and pay on the Georgia Tax Center. If the client owes $500.00 or less and does not pay by EFT, the DOR says a paper return on Form ST-3 is allowed.
Failure mode: a client paid by ACH for one period, then sends a paper ST-3 for the next. The DOR penalty page sets the failure-to-file-electronically line at the greater of $25 or 5% of the tax due before payments or credits. On a return with $500.00 of tax, 5% is $25, the same as the floor. Above $500.00 of tax, the 5% line governs.
Penalty math for late returns and late payments
The DOR penalty page cites O.C.G.A. 48-8-66 for the late-return line: the greater of 5% of the tax or $5, plus an additional 5% or $5 for each additional late month, with a maximum of the greater of 25% of the tax or $25.
Worked example one: a return with $500.00 of tax filed two months late. Each late month adds 5% of the tax, which is $25, so two months add 10%. The cap is 25% of the tax, which is larger than $25, so it does not bind yet.
Worked example two: the same $500.00 return filed six months late. Five late months reach the 25% cap, so the penalty stops growing after the fifth month, and the sixth month adds nothing.
The DOR summary lists a failure-to-pay line with the same rate and maximum as the late-return line, and says it applies regardless of whether the return is filed. Do not assume a late return with a late payment is penalized once. Read the notice to see which lines were assessed before you explain the amount to the client.
Interest on past due tax
The DOR says interest on past due sales and use tax accrues monthly from the date the tax is due until the date it is paid. The rate is the Federal Reserve prime rate plus 3 percent, under O.C.G.A. 48-2-40, and the DOR says the rate may be adjusted each January.
To estimate one month of interest, multiply the unpaid tax by the annual rate and divide by 12, using the rate for the calendar year in which the interest accrues. Confirm the current rate with the DOR before quoting a number to a client.
Send this sentence as written: "Your September 2026 sales tax was due October 20, 2026. Interest runs from that date until the tax is paid." Do not quote an interest amount until the rate is confirmed.
Failure modes and what fixes them
Wrong frequency on the calendar. Fix: pull the account record and rebuild the calendar from the DOR table for that frequency.
A local rate taken from an old chart. Fix: check the effective and end dates on the current DOR chart row for the jurisdiction and sale month, and record the chart's effective date in the workpaper.
A late return with a payment on time. Fix: the two lines are separate, so a timely payment does not cure a late return. File and pay on the same date.
A false or fraudulent return. The DOR summary lists a penalty of 50% of the tax due for that case. Any figure that looks inconsistent with the sales records goes to the owner before filing.
What to send the client
Client request for the October 2026 period, due 11/20/2026: "Please send taxable sales for October 2026 split by city or county, with the sales report or invoice that shows where each sale was delivered." Ask for it by November 16, 2026 so the return can be filed by November 20.
Client request for the account: "Please log in to the Georgia Tax Center and send me the filing frequency and filing method on your sales and use tax account, with a screenshot of that page." Send this with the first request.