Massachusetts Sole Proprietorship Tax Deadlines 2026

When is the Sole Proprietorship tax filing deadline in Massachusetts for 2026?

The Massachusetts Sole Proprietorship tax return is due Apr 15, 2026 for the 2026 tax year. An extension is available until Oct 15, 2026.

Does Massachusetts require Sole Proprietorship estimated tax payments?

Yes, Massachusetts requires estimated tax payments for Sole Proprietorship entities. The quarterly due dates are: Apr 15, 2026, Jun 16, 2026, Sep 15, 2026, Jan 15, 2027. Penalties may apply if you underpay or miss a deadline.

What form do I file for a Sole Proprietorship in Massachusetts?

Sole Proprietorship entities in Massachusetts file using Form Form 1 / 1-NR/PY. You can download the form from Massachusetts Department of Revenue at https://www.mass.gov/orgs/massachusetts-department-of-revenue.

Can I get an extension for my Massachusetts Sole Proprietorship tax return?

Yes. Massachusetts allows an extension for Sole Proprietorship returns until Oct 15, 2026. Note that an extension gives you more time to file, not more time to pay — any tax owed is still due by the original deadline of Apr 15, 2026.

What are the penalties for filing late in Massachusetts?

Massachusetts typically charges a failure-to-file penalty (usually 5% of unpaid tax per month, up to 25%) and a failure-to-pay penalty (usually 0.5-1% per month). Interest also accrues on unpaid balances. Filing for an extension by the original deadline avoids the failure-to-file penalty but not the failure-to-pay penalty.

Where can I file Massachusetts Sole Proprietorship taxes?

File through Massachusetts Department of Revenue. Visit https://www.mass.gov/orgs/massachusetts-department-of-revenue for e-filing options, downloadable forms, and payment portals.