US Sales Tax Deadline: 21 September 2026
If you collect US sales tax, Monday 21 September 2026 is a critical filing and payment deadline in many jurisdictions. The usual 20th-of-the-month deadline fell on Sunday, so a large group of states moved the deadline to the next business day.
This applies to international ecommerce sellers, Amazon FBA operators, Shopify merchants, digital businesses, and US importers of record. It may cover monthly returns, prepayments, quarterly returns, or related payments depending on your filing frequency.
Do not assume every state uses 21 September. Several states have different dates.
File today if your state uses the 20th-of-the-month deadline
The following states and jurisdictions generally move their standard 20th-of-the-month sales tax deadline to Monday 21 September 2026 because 20 September fell on a Sunday:
- Alabama
- Arizona
- Arkansas
- Colorado, including most home-rule city returns
- District of Columbia
- Georgia
- Hawaii General Excise Tax
- Idaho
- Illinois
- Indiana, for early monthly filers
- Kentucky
- Louisiana, where parish deadlines generally align
- Maryland
- Michigan
- Minnesota
- Mississippi
- Nebraska
- Nevada
- New Jersey, for monthly prepayments; returns are generally filed quarterly
- New York, for monthly and quarterly returns
- North Carolina, where monthly prepayment filers must also remit a prepayment towards the next month’s liability
- Oklahoma
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Virginia
- West Virginia
- Wisconsin, for early monthly filers
Your filing obligation depends on the frequency assigned to your account. A monthly seller may be filing an August return. A quarterly seller may be filing a return covering the previous quarter. Some states may require a prepayment rather than the full return.
Check the relevant state revenue department before submitting. For example, New York’s 2026 filing calendar explains the state’s monthly and quarterly sales tax filing dates, while Colorado’s sales tax guidance sets out its filing rules and weekend adjustments.
Do not treat 21 September as a nationwide deadline
Several states follow different dates in September. Your compliance calendar should include the following deadlines:
- Maine: 15 September
- Florida: 18 September
- Ohio: 23 September
- Kansas, New Mexico, Vermont and Washington: 25 September
- California, Connecticut, Iowa, Massachusetts, Missouri, North Dakota, Utah and Wyoming: 30 September
- Wisconsin: 30 September for standard monthly filers
- Alaska: generally 30 September for remote seller returns in participating local jurisdictions
California also has a separate 24 September prepayment deadline for certain accounts. Its monthly August sales and use tax return is generally due on 30 September. The California Tax and Fee Filing Due Dates page confirms these dates.
North Dakota’s monthly August sales, use and gross receipts tax return and payment are due on 30 September, according to the state’s official 2026 deadline schedule.
If you missed a deadline earlier this month, submit the return and payment as soon as possible. Late filing can lead to penalties, interest, or compliance notices.
Marketplace collection does not remove your filing obligation
All 45 states with a statewide general sales tax plus the District of Columbia have marketplace facilitator laws. Amazon, Etsy and similar platforms may collect and remit sales tax on transactions processed through their marketplaces.
However, marketplace collection does not automatically eliminate your own filing obligations.
You may still need to:
- Maintain an active sales tax registration.
- File a zero return where no tax is payable.
- Report marketplace sales separately from direct sales.
- Make required prepayments.
- File quarterly or annual returns.
- Report sales made through your own website.
- Account for wholesale, B2B and other non-facilitated transactions.
Your Shopify store is not automatically covered simply because Amazon collects tax on your Amazon orders. Direct-to-consumer sales may create separate collection and reporting obligations.
Alaska, Delaware, Montana, New Hampshire and Oregon do not have a statewide sales tax. Alaska is different because local jurisdictions may impose their own remote seller and marketplace collection requirements.
Complete this checklist before the end of today
Use the following process to reduce the risk of a missed return.
-
List every state and local jurisdiction where you are registered.
This prevents you from relying on a general national calendar. -
Confirm your filing frequency.
Check whether the account is monthly, quarterly, annual, or subject to prepayments. -
Separate marketplace and direct-channel sales.
Reconcile Amazon, Etsy and other platform reports with Shopify, WooCommerce, wholesale and B2B invoices. -
Review exempt and resale transactions.
Keep valid exemption certificates and resale documentation. This supports the figures on your return. -
Check import and fulfilment records.
If you are the importer of record, review customs entries, warehouse movements, use tax exposure and inventory destinations. -
Submit the return, even if the liability is zero.
A zero return may still be required. Filing it protects your account from an apparent non-filing notice. -
Schedule or make the payment.
Filing without paying the balance can still result in interest and collection action. -
Save evidence of submission.
Keep confirmation numbers, payment references, filed returns and reconciliation workpapers.
We can support this process through ongoing bookkeeping, sales tax calculations, filing preparation and compliance delivery. You provide the business data. We keep the compliance work moving throughout the year.
Worked example: a UK-owned Amazon FBA seller with a US LLC
Imagine a UK company owner operates a US single-member LLC. The LLC sells household products through Amazon FBA and Shopify.
Amazon collected and remitted sales tax on many marketplace transactions. The seller therefore assumes there is nothing to file.
That assumption may be incorrect.
The seller should first review the states where the LLC is registered or has a filing account. Suppose the business has filing obligations in Texas, Illinois, New York and California.
The September action could look like this:
- Texas: file and pay the relevant August return by 21 September.
- Illinois: file and pay the relevant monthly return by 21 September.
- New York: file and pay the relevant monthly or quarterly return by 21 September.
- California: make the 24 September prepayment if applicable, and file and pay the monthly August return by 30 September.
The seller then finishes the process by:
- Filing any zero returns required in states where only marketplace sales were made.
- Keeping all confirmation numbers and reconciliation workpapers.
That final step often matters most during a later audit.
