Tax Calendar: September and October 2018


SEPTEMBER 2018

 

September 17

Individuals. If you are not paying your 2018 income tax through withholding (or will not pay in enough tax during the year that way), pay the third installment of your 2018 estimated tax. Use Form 1040-ES.

Employers. For Social Security, Medicare, withheld income tax, and nonpayroll withholding, deposit the tax for payments in August if the monthly rule applies.

Corporations. Deposit the third installment of estimated income tax for 2018. Use the worksheet Form 1120-W to help estimate tax for the year.

Partnerships. File a 2017 calendar-year return (Form 1065). This due date applies only if you timely requested an automatic 6-month extension. Provide each partner with a copy of their final or amended Schedule K-1 (Form 1065) or substitute Schedule K-1.

S corporations. File a 2017 calendar-year income tax return (Form 1120S) and pay any tax, interest, and penalties due. This due date applies only if you timely requested an automatic 6-month extension. Provide each shareholder with a copy of Schedule K-1 (Form 1120S) or a substitute Schedule K-1.

 

OCTOBER 2018

 

October 15

Individuals. If you have an automatic six-month extension to file your income tax return for 2017, file Form 1040, 1040A, or 1040EZ and pay any tax, interest, or penalties due.

Employers. For Social Security, Medicare, withheld income tax, and nonpayroll withholding, deposit the tax for payments in September if the monthly rule applies.

Corporations. File a 2017 calendar-year income tax return (Form 1120) and pay any tax, interest, and penalties due. This due date applies only if you timely requested an automatic 6-month extension.

 

October 31

Employers. For Social Security, Medicare, and withheld income tax, file Form 941 for the third quarter of 2018. Deposit any undeposited tax. (If your tax liability is less than $2,500, you can pay it in full with a timely filed return.) If you deposited the tax for the quarter in full and on time, you have until November 13 to file the return.

For federal unemployment tax, deposit the tax owed through September if more than $500.