Here are some of the key tax-related deadlines affecting businesses and other employers during the fourth quarter of 2018. Keep in mind that this list isn’t all-inclusive, so there may be additional deadlines that apply to you.

October 15

  • If a calendar-year C corporation that filed an automatic six-month extension:
  • File a 2017 income tax return (Form 1120) and pay any tax, interest and penalties due.
  • Make contributions for 2017 to certain employer-sponsored retirement plans.

October 31

  • Report income tax withholding and FICA taxes for third quarter 2018 (Form 941) and pay any tax due. (See exception below under “November 13.”)

November 13

  • Report income tax withholding and FICA taxes for third quarter 2018 (Form 941), if you deposited on time and in full all of the associated taxes due.

December 17

  • If a calendar-year C corporation, pay the fourth installment of 2018 estimated income taxes.

Contact us to ensure you’re meeting all applicable deadlines and to learn more about the filing requirements.

To avoid interest and penalties, you must make sufficient federal income tax payments long before your April filing deadline through withholding, estimated tax payments, or a combination of the two. The third 2018 estimated tax payment deadline for individuals is September 17.

If you don’t have an employer withholding tax from your pay, you likely need to make estimated tax payments. But even if you do have withholding, you might need to pay estimated tax. It can be necessary if you have more than a nominal amount of income from sources such as self-employment, interest, dividends, alimony, rent, prizes, awards or the sales of assets.

A Two-Prong Test
Generally, you must pay estimated tax for 2018 if both of these statements apply:

  1. You expect to owe at least $1,000 in tax after subtracting tax withholding and credits, and
  2. You expect withholding and credits to be less than the smaller of 90% of your tax for 2018 or 100% of the tax on your 2017 return — 110% if your 2017 adjusted gross income was more than $150,000 ($75,000 for married couples filing separately).

If you’re a sole proprietor, partner or S corporation shareholder, you generally have to make estimated tax payments if you expect to owe $1,000 or more in tax when you file your return.

Quarterly Payments
Estimated tax payments are spaced through the year into four periods or due dates. Generally, the due dates are April 15, June 15 and September 15 of the tax year and January 15 of the next year, unless the date falls on a weekend or holiday (hence the September 17 deadline this year).

Estimated tax is calculated by factoring in expected gross income, taxable income, deductions and credits for the year. The easiest way to pay estimated tax is electronically through the Electronic Federal Tax Payment System. You can also pay estimated tax by check or money order using the Estimated Tax Payment Voucher or by credit or debit card.

Confirming Withholding
If you determine you don’t need to make estimated tax payments for 2018, it’s a good idea to confirm that the appropriate amount is being withheld from your paycheck. To reflect changes under the Tax Cuts and Jobs Act (TCJA), the IRS updated the tables that indicate how much employers should withhold from their employees’ pay, generally reducing the amount withheld.

The new tables might cause some taxpayers to not have enough withheld to pay their ultimate tax liabilities under the TCJA. The IRS has updated its withholding calculator (available at irs.gov) to assist taxpayers in reviewing their situations.

Avoiding Penalties
Keep in mind that, if you underpaid estimated taxes in earlier quarters, you generally can’t avoid penalties by making larger estimated payments in later quarters. But if you also have withholding, you may be able to avoid penalties by having the estimated tax shortfall withheld.

While April 15 (April 17 this year) is the main tax deadline on most individual taxpayers’ minds, there are others through the rest of the year that you also need to be aware of. To help you make sure you don’t miss any important 2018 deadlines, here’s a look at when some key tax-related forms, payments and other actions are due. Keep in mind that this list isn’t all-inclusive, so there may be additional deadlines that apply to you.

June 15
• File a 2017 individual income tax return (Form 1040) or file for a four-month extension (Form 4868), and pay any tax and interest due, if you live outside the United States.
• Pay the second installment of 2018 estimated taxes, if not paying income tax through withholding (Form 1040-ES).

September 17
• Pay the third installment of 2018 estimated taxes, if not paying income tax through withholding (Form 1040-ES).

October 1
• If you’re the trustee of a trust or the executor of an estate, file an income tax return for the 2017 calendar year (Form 1041) and pay any tax, interest and penalties due, if an automatic five-and-a-half month extension was filed.

October 15
• File a 2017 income tax return (Form 1040, Form 1040A or Form 1040EZ) and pay any tax, interest and penalties due, if an automatic six-month extension was filed (or if an automatic four-month extension was filed by a taxpayer living outside the United States).
• Make contributions for 2017 to certain retirement plans or establish a SEP for 2017, if an automatic six-month extension was filed.
• File a 2017 gift tax return (Form 709) and pay any tax, interest and penalties due, if an automatic six-month extension was filed.

December 31
• Make 2018 contributions to certain employer-sponsored retirement plans.
• Make 2018 annual exclusion gifts (up to $15,000 per recipient).
• Incur various expenses that potentially can be claimed as itemized deductions on your 2018 tax return. Examples include charitable donations, medical expenses and property tax payments.

But remember that some types of expenses that were deductible on 2017 returns won’t be deductible on 2018 returns under the Tax Cuts and Jobs Act, such as unreimbursed work-related expenses, certain professional fees, and investment expenses. In addition, some deductions will be subject to new limits. Finally, with the nearly doubled standard deduction, you may no longer benefit from itemizing deductions.