August 20 Is 10 Days Away. Here's Every Sales Tax Deadline You Cannot Miss This Month.
August 20 is 10 days away.
For monthly sales tax filers, that's the deadline to report and remit July's transactions in most states. For quarterly filers, Q3 is underway — and the decisions you make now about nexus, rate accuracy, and exemption certificates will determine whether your October return is clean or complicated.
Sales tax compliance rarely breaks because of a calculation error. It breaks because filing obligations quietly multiply across states. Monthly in one state. Quarterly in another. A non-standard deadline somewhere else. Miss one and penalties start compounding — even when the tax itself was calculated correctly. Sails
Here's every August deadline, every non-standard state, and everything quarterly filers should be doing right now.
The Standard August 20 Deadline — Who It Covers
Most states have due dates on the 20th of the month for monthly filers. August 20 falls on a Thursday in 2026 — a standard business day, no weekend shift needed. Salestaxes
The states on the standard August 20 deadline include Alabama, Arizona, Arkansas, Colorado, Connecticut, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Jersey, New York, North Carolina, North Dakota, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, West Virginia, Wisconsin, and Wyoming.
That's the majority of the country. If you file in any of these states, August 20 is your date — with two important exceptions covered below.
Florida: The Electronic Payment Trap
Florida is the most commonly missed deadline for ecommerce businesses — and the reason is a rule most sellers don't know exists.
Florida is the exception for electronic payments, which must be initiated the business day before the 20th. Ceretax
That means Florida's effective deadline for electronic filers isn't August 20 — it's August 19. If you initiate your Florida payment on August 20, it's late. The penalty clock starts immediately.
This rule catches businesses off guard every month. If you file Florida electronically — which most businesses do — put August 19 on your calendar as the actual action date, not August 20.
Texas: August Sales Due September 21 — Not September 20
Texas monthly filers covering July transactions have their return due August 20 — standard. But here's what forward-planning businesses need to know for next month.
Texas's August sales tax return — covering August transactions — is due September 21, not September 20, because the 20th falls on a weekend in September. Salestaxsolutions
If you're Texas-registered and managing your own filing calendar, mark September 21 for your August return. Texas's comptroller does not automatically alert you to adjusted dates.
The Comptroller assesses a $50 penalty per late return immediately, plus 5% of any tax due if you file within 30 days of the deadline, or 10% if you are more than 30 days late. Salestaxsolutions
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The Non-Standard State Deadlines
Not every state uses the 20th. Here's where August looks different:
Maine — August 15 (already passed).
Maine is the only state with deadlines on the 15th of the month. If you file in Maine and missed August 15, file immediately — penalties are already accruing at 1% per month up to 25% of tax due.
Ohio — August 23.
Ohio is the only state with deadlines on the 23rd of the month. Ohio monthly filers have until August 23 — three extra days over the standard deadline. Salestaxes
Washington — August 25.
Washington has deadlines on or before the 25th of the month. Washington monthly filers have until August 25. Given Washington's complex rate structure — 864 local rate changes hit July 1 — verify your July returns reflect the updated rates before filing.
Kansas, New Mexico, Vermont — August 25.
Kansas, New Mexico, and Vermont have deadlines on the 25th or the next business day. All three are due August 25 for monthly filers. Salestaxes
Massachusetts — August 30.
Massachusetts is the only state with deadlines on or before the 30th every month. Massachusetts monthly filers have until August 30 — the latest standard deadline of any state. Note: if you had Massachusetts sales during the August 8-9 tax-free weekend, verify your system correctly exempted qualifying items during that window before filing.
California — August 31.
California monthly filers have until August 31. California's combined rates vary significantly by jurisdiction — verify your July filings reflect any local rate changes that took effect July 1 in your delivery ZIP codes, including the Mecklenburg County-style changes in California jurisdictions.
Alaska — August 31.
Alaska has no statewide sales tax, but local jurisdictions collect their own — and many use month-end deadlines. If you're registered in Alaskan localities, verify your specific due dates.
The Back-to-School Holiday Wrinkle
August's filing period overlaps with one of the most compliance-intensive weekends of the year — the August 7-9 multi-state holiday cluster.
If you filed returns in Iowa, Texas, Ohio, Missouri, Oklahoma, South Carolina, Virginia, Illinois, or Massachusetts, your July return is straightforward. But your August return — due in September — will include the holiday weekend transactions.
Here's what that means for each state:
Iowa: Your August return covers August 7-8 holiday transactions. Those transactions need to show qualifying clothing and footwear as exempt — zero tax collected. Verify your system applied the exemption correctly before those transactions hit your September return.
Texas: August 7-9 holiday transactions are included in your August return due September 21. Qualifying clothing, footwear, school supplies, and backpacks under $100 should show as tax-exempt. Verify before filing.
Ohio: August 7-9 holiday transactions in your August return need to reflect the traditional format only — clothing under $75, supplies under $20. If your system was accidentally configured for the expanded format, audit your August transactions now before filing the return.
Illinois: August 7-16 holiday transactions show a reduced 1.25% state rate on qualifying items — not zero. Verify your August Illinois return correctly shows the reduced state rate with local taxes unchanged. This is the most technically complex of the holiday configurations to verify in post-period audit.
Massachusetts: August 8-9 holiday transactions should show most qualifying items under $2,500 as fully exempt. Mandatory participation means you were required to apply the exemption — any August Massachusetts return showing tax collected on qualifying items during those two days creates an over-collection liability.
What Quarterly Filers Should Be Doing Right Now
If you file quarterly rather than monthly, your Q3 return isn't due until October 20. But August is the month to get ahead of it — not to wait.
Quarterly filers are typically due January 20, April 20, July 20, and October 20. Your Q3 covers July 1 through September 30. Here's what to focus on now:
Review your July 1 rate change compliance. July 1 brought 1,340 sales tax changes across 20-plus states. Illinois processed 202 local rate changes. Washington processed 864. Mecklenburg County's rate jumped from 7.25% to 8.25%. Alabama's grocery tax suspension ended. Colorado's retail delivery fee increased. Nebraska repealed multiple exemptions. If any of these affected your delivery jurisdictions, verify your Q3 collections reflect the updated rates from July 1 onward — not the prior rates.
Assess new nexus states. If your sales crossed an economic nexus threshold in a new state during Q2 — which ended June 30 — you may have had a Q2 filing obligation you missed. Address historical exposure now before Q3 adds another period on top of it.
Check Indiana's tax amnesty window. Indiana's amnesty program runs July 15 through September 9 — covering pre-2024 liabilities with full penalty and interest waivers. If you have Indiana back-tax exposure, the amnesty window closes September 9. That's 30 days away.
Renew expired exemption certificates. Any resale or exemption certificate that expired during Q2 or early Q3 needs to be renewed before you file your October return. Missing certificates are a primary audit trigger — especially in states where AI-powered audit selection is now standard.
Monitor Connecticut's August 16-22 holiday. Connecticut's expanded tax-free week — with the new $300 threshold and backpacks added as a qualifying category — runs August 16-22. If you sell clothing or footwear into Connecticut, your Q3 return will include holiday-period transactions that need to be correctly configured as exempt.
The Zero Return Requirement — The Rule Most Businesses Forget
Even if you collected zero sales tax in a period, most states still require you to file a zero return. Skipping it triggers the same late penalties as if you owed money.
This is one of the most common compliance mistakes for businesses that expanded into new states and then had a slow month. Registering in a state creates a filing obligation — permanently, until you formally close your account. A month with no taxable sales doesn't mean no filing requirement. It means a zero return is due on the same schedule as every other month.
If you registered in any new states in Q1 or Q2 and had months with no taxable sales into those states, verify zero returns were filed on time. States with automated matching systems are increasingly flagging registered businesses that have gaps in their filing history — even zero-liability gaps.
The Penalty Stakes
Missing a sales tax due date can lead to a whole world of pain. Penalties and interest add up quickly and can dramatically cut into your profits. Worse, repeatedly missing a due date can trigger audits or damage your reputation with state tax agencies who'll flag you as a compliance risk. Ortholo
Here's what's at stake in the states where penalties hit hardest:
Washington — 9% after the due date, 19% after the last day of the following month, up to 29% after the second month. The steepest penalty structure in the country.
California — 10% of tax due for late filing, plus daily interest. For high-volume sellers, a missed California deadline is expensive fast.
Texas — $50 per late return immediately, plus 5% of tax due within 30 days, 10% beyond 30 days.
Illinois — 2% penalty on unpaid tax, plus 20% if the return isn't filed within 30 days.
New York — 10% for late filing, with additional penalties for repeat late filers.
Your August Compliance Checklist
Ten days is enough time to handle everything — if you start today.
For monthly filers: Reconcile your July transaction data by jurisdiction. Verify rate accuracy — especially for jurisdictions affected by July 1 rate changes. Confirm Florida's electronic payment initiates August 19, not August 20. File Maine immediately if you missed August 15.
For back-to-school holiday states: Audit your August 7-9 holiday transactions before September filings. Verify Illinois shows the reduced 1.25% state rate — not zero — on qualifying items. Confirm Massachusetts holiday exemptions were applied correctly.
For quarterly filers: Review Q3 July collections for rate accuracy. Assess Indiana amnesty eligibility before September 9. Check for expired exemption certificates. Monitor Connecticut's August 16-22 holiday for Q3 return accuracy.
For all businesses: File zero returns on time for every registered state with no taxable sales. Verify your filing frequency hasn't been changed by a state without your noticing — states can adjust filing frequency as your revenue grows, often without prominent notification.
Not sure whether your August filings are on track across all your registered states — or concerned that the July 1 rate changes created compliance gaps in your Q3 records? Book a free consultation with our team at sales.tax. We'll audit your filing calendar, verify your rate accuracy, and make sure nothing falls through the cracks before August 20.
What this means for your business
Thresholds move, rules change, and nobody tells you when you cross one. We’ll tell you where you stand in 30 minutes — and if there’s nothing to fix, we’ll say so.