You file Massachusetts sales tax online in MassTaxConnect, the Department of Revenue's (DOR) web portal, using Form ST-9, the Sales and Use Tax Return. Monthly and quarterly returns are due on or before the 30th day after the period ends.
This guide covers who files and how often, what to have ready, due dates, zero returns, payment rules, and penalties for late returns.
This article is educational information, not tax advice. Filing rules, thresholds, and penalties can change, so confirm current requirements with the Massachusetts DOR before you file.
Massachusetts sales tax filing at a glance
- Who administers it: Massachusetts Department of Revenue.
- Online portal: MassTaxConnect. You must register with DOR before you can use it.
- Return: Form ST-9, Sales and Use Tax Return.
- State rate: 6.25%.
- Filing frequency: Monthly, quarterly, or annual, based on your estimated yearly sales and use tax liability.
- Due date: The 30th day after the end of the period.
- Zero returns: Required for most tax types, even when no tax is due.
- Payment: Electronic funds transfer (EFT) debit through MassTaxConnect is DOR's preferred method. DOR requires sales and use tax filers to file and pay electronically.
- Economic nexus for remote sellers: More than $100,000 in Massachusetts sales in the prior or current calendar year.
Who has to file, and how often
Every registered Massachusetts vendor files sales and use tax returns. That includes out-of-state sellers that register after crossing the state's economic nexus threshold: a remote seller whose Massachusetts sales exceed $100,000 in either the prior or current calendar year must register, collect tax, and remit it to DOR. Our Massachusetts sales tax guide covers registration and nexus in more detail. Selling software? Our post on Massachusetts SaaS sales tax explains how it is treated there.
Your filing frequency depends on the sales and use tax liability you estimate for the calendar year:
| Frequency | When it applies | Due date |
|---|---|---|
| Monthly | Estimated liability over $1,200 for the calendar year | 30th day after the month ends |
| Quarterly | Estimated liability over $100 but not more than $1,200 | 30th day after the quarter ends |
| Annual | Estimated liability of $100 or less | 30th day after the year ends |
The schedule you choose when your first return is due applies for the whole calendar year, and you cannot change it yourself mid-year. If you pay more or less than you estimated, DOR moves you to the correct schedule the following year.
Before you start: set up MassTaxConnect
MassTaxConnect is where Massachusetts business taxpayers file returns, make payments, and manage their accounts. To file your first return:
- Register with DOR. You need a MassTaxConnect account tied to your sales tax registration before you can file online. Our sales tax permit overview explains the registration process.
- Log in and open your sales and use tax account. Review the Form ST-9 instructions first so you know which lines apply to you.
- Have your records ready. ST-9 asks for the total of your Massachusetts sales, leases, and rentals of tangible personal property for the period, plus the use tax you owe on items you bought without paying Massachusetts tax. For sales to resellers, see our Massachusetts resale certificate guide.
Step-by-step: filing Form ST-9 in MassTaxConnect
- Log in to MassTaxConnect and go to your sales and use tax return for the period.
- Report your Massachusetts sales. Line 1 of ST-9 is the sum of all Massachusetts sales, leases, and rentals of tangible personal property. Enter the amounts the form asks for from your sales records.
- Report use tax. If you bought taxable items without paying Massachusetts sales or use tax, the use tax is reported on the return as well.
- Review the total amount due. ST-9 works out the total from your sales tax and use tax, less any credit the form allows, such as prepaid sales tax on tobacco products.
- Submit and pay. Pay by EFT debit from MassTaxConnect, or by another electronic method DOR accepts.
- Keep your confirmation with your records for the period.
To change a return you already filed, use the adjustment process described in DOR's MassTaxConnect filing guidance.
Filing in Massachusetts plus other states?
If you file in more than one state, or you would rather not log in to MassTaxConnect every period, Kintsugi files and remits for you. Filing starts at $75 per filing, monitoring is free, and there is no per-state subscription. Start free or book a demo.
Due dates
Massachusetts changed sales and use tax due dates from the 20th to the 30th day after the period for periods ending after April 1, 2021. Today:
- Monthly returns are due on or before the 30th day following the month.
- Quarterly returns are due on or before the 30th day following the quarter (January to March, April to June, July to September, October to December).
- Annual returns are due on or before the 30th day following the year.
Older calendars and forms that still show the 20th are out of date. Advance payments apply on top of this schedule for larger filers: taxpayers with more than $150,000 in cumulative tax liability in the prior year must make advance payments. See DOR's advance payment guidance to find out whether that applies to you. Our Massachusetts sales tax due dates page lists upcoming dates for every state.
Filing a zero return
For most tax types in Massachusetts, you must file a return even if you have no tax due for the period. DOR imposes penalties if you do not file, even when you have nothing to report. File the ST-9 in MassTaxConnect with zero amounts for any period in which you made no taxable sales.
Payment methods and electronic filing rules
MassTaxConnect gives you the option to pay by EFT debit, which DOR describes as its preferred method. The other electronic option is an ACH credit, where you instruct your bank to send the payment in the format DOR requires.
Electronic filing and payment are mandatory for sales and use tax. DOR's e-filing page lists sales and use among the taxes that must be filed and paid electronically, with a narrow exception for some businesses registered before September 1, 2003 whose combined tax liability stays under $5,000 a year. A return that must be e-filed but is filed on paper will not be processed.
Penalties for late filing and late payment
- Late return: 1% of the tax required to be shown on the return for each month or part of a month the return is late, up to 25%.
- Late payment: 1% of the unpaid tax for each month or part of a month, up to 25%.
- Abatement: DOR may waive or abate late filing and late payment penalties, in whole or in part, if you show the failure was due to reasonable cause and not willful neglect.
Common mistakes to avoid
- Skipping zero returns. A period with no sales still needs a return.
- Using the old due date. Returns are due on the 30th day after the period, not the 20th.
- Changing frequency mid-year. DOR adjusts your schedule the following year, not during the current one.
- Filing on paper. DOR does not process a return that must be e-filed if it arrives on paper.
- Ignoring remote-seller nexus. Crossing $100,000 in Massachusetts sales in the prior or current year triggers registration and collection.
More state filing guides
Filing in more than one state? These step-by-step guides cover the portals, due dates, and penalties in other states. See them all in our state-by-state guide to filing sales tax online.
- How to file New Jersey sales tax online
- How to file New York sales tax online
- How to file Pennsylvania sales tax online
Frequently asked questions
How do I file Massachusetts sales tax online?
Log in to MassTaxConnect and file Form ST-9, the Sales and Use Tax Return. You must register with DOR first.
When is Massachusetts sales tax due?
Monthly returns are due on or before the 30th day after the month, and quarterly returns on or before the 30th day after the quarter. Annual returns are due on or before the 30th day after the year.
Do I have to file if I had no sales?
Yes. For most tax types, DOR requires a return even when no tax is due, and it can penalize you for not filing.
How do I choose or change my filing frequency?
Your frequency follows your estimated annual sales and use tax liability: annual at $100 or less, quarterly above $100 up to $1,200, and monthly above $1,200. You cannot change it yourself during the calendar year. DOR adjusts it the following year if your actual liability differs from your estimate.
What is the Massachusetts economic nexus threshold?
A remote seller with more than $100,000 in Massachusetts sales in the prior or current calendar year must register as a vendor, collect tax, and remit it to DOR.
What happens if I file or pay late?
DOR adds a 1% penalty for each month or part of a month, up to 25%, for a late return and separately for late payment. Penalties may be abated for reasonable cause.
Let Kintsugi handle Massachusetts filing
Kintsugi's sales tax filing software prepares and files your Massachusetts returns on your assigned schedule, including zero returns, and remits the payment. You review the numbers; Kintsugi handles the portal. Filing starts at $75 per filing, with free monitoring across every US state and no per-state subscription. See pricing, check rates with the Massachusetts sales tax calculator, or start free.
Sources
Checked September 29, 2026.
- Massachusetts DOR, Sales and Use Tax
- Massachusetts DOR, Form ST-9 Instructions: Sales and Use Tax Return
- Massachusetts DOR, Filing Returns in MassTaxConnect
- Massachusetts DOR, Making Payments in MassTaxConnect
- Massachusetts DOR, Tax Due Dates and Extensions
- Massachusetts DOR, New Due Date for Sales and Use Tax Returns
- 830 CMR 62C.16.2, Sales and Use Tax Returns and Payments
- Massachusetts DOR, DOR E-filing and Payment Requirements
- Massachusetts DOR, Remote Seller and Marketplace Facilitator FAQs
- Massachusetts DOR, Penalties and Interest Assessed by DOR
