Here is a calendar of the key tax-filing deadlines for 2014.

TIP: Bookmark this tax calendar for reference during the year.

Note: If a regular due date falls on a weekend or a national holiday, it is postponed to the next business day.

If you operate on a fiscal-year schedule for tax purposes, rather than the usual calendar-year schedule, your due dates for each quarter will line up differently. Using the 2014 calendar, here's how you should calculate your deadlines:

Personal tax deadlines

Annual tax returns. Your personal tax return (Form 1040) is due on the 15th day of the fourth month following the close of your tax year.
Estimated tax payments. The first three quarterly installments of estimated tax (Form 1040-ES) are due on the 15th day of the fourth, sixth and ninth months of your tax year. The fourth and final installment is due on the 15th day of the first month following the close of your tax year.

Corporate tax deadlines

Annual tax returns. Your annual corporate return (Form 1120 or 1220-S) is due on the 15th day of the third month following the close of your corporation's tax year. S corporations must provide each shareholder with a copy of Schedule K-1 or a substitute Schedule K-1.
Estimated tax payments. The quarterly installments of estimated taxes are due on the 15th day of the fourth, sixth, ninth and 12th months of the corporation's tax year.
Switching to an S corp. The deadline is the 15th day of the third month of the year in which you want the election to apply. Make the election anytime in the preceding tax year (Form 2553).

Partnership tax deadlines

Annual returns. Your annual partnership return (Form 1065) is due on the 15th day of the fourth month following the close of the partnership's tax year. Partnerships must provide each partner with a copy of Schedule K-1 or a substitute Schedule K-1.

JANUARY

Employers. Prepare copies of W-2s for 2013, and give them to your employees by Jan. 31. If an employee agreed to receive his or her W-2 electronically, post it and notify the worker by Jan. 31.

Thursday, Jan. 2
Employers. Stop advance payments of earned income credit For any employee who did not give you a new Form W-5 for 2014.

Wednesday, Jan. 15
Personal. Pay the fourth-quarter and final estimated-tax payment for the year 2013 with Form 1040-ES. You don't have to make this payment if you file your 2013 return (Form 1040) and pay any tax due by Jan. 31, 2014.
Employers. December 2013 payroll tax deposit is due if you're not on a semiweekly deposit schedule.

Friday, Jan. 31
Personal. File your 2013 income tax return (Form 1040) if you did not make a fourth-quarter estimated payment by Jan. 15.

Businesses. Give Form 1099 information statements to the recipients of certain payments you made for services during 2013. This can include independent contractor compensation, interest on seller financed mortgages, rent, professional services fees, real estate transactions, profit-sharing and pension plan distributions. Also, submit statements to customers who paid you more than $10,000 in any single cash transaction during 2013. (For details, see instructions for Form 8300, Report of Cash Payments Over $10,000 Received in a Trade or Business.)

Employers. File Form 941 (payroll tax) for the fourth quarter of 2013 and deposit any unpaid taxes. File Form 940 (federal unemployment tax) for 2013. File Form 945 to report income tax withheld for 2013 on all non-payroll items, such as pensions, annuities and IRAs. File Form 944 for the 2013 tax year if your employment tax liability was $1,000 or less.

FEBRUARY

Tuesday, Feb. 18
Personal. File a new Form W-4 with your employer to change your withholding or continue the exemptions claimed in 2013.
Employers. January 2014 payroll tax deposit is due if you're not on a semiweekly deposit schedule. Also, begin for 2014 withholding income tax from the pay of any employee who claimed exemptions in 2013 but did not give you a new Form W-4 to continue the exemptions this year.

Friday, Feb. 28
Employers. Send Form W-3, Transmittal of Wage and Tax Statements, to the IRS along with Copy A of all employee W-2s you issued in 2014 for calendar-year 2013.
Businesses. Send Forms 1099 and 1096 to the IRS (see Jan. 31). A separate 1096 is required for each 1099 type.

MARCH

Monday, March 17
C corporations. File a 2013 calendar-year income tax return (Form 1120 or 1120-A) and pay any tax that is due. If you want an automatic six-month extension, file Form 7004, and deposit what you estimate you owe.
S corporations. File your 2013 calendar-year income tax return (Form 1120-S) and pay any tax that is due. Provide each shareholder with a copy of Schedule K-I (Form 1120-S), Shareholder's Share of Income, Deductions, Credits, etc., or a substitute Schedule K-1. For an automatic six-month extension, file Form 7004.
S corporation election. File Form 2553, Election by a Small Business Corporation, by this date to be treated as an S corp beginning with calendar-year 2014. If you miss the deadline, the switch generally won't take effect until calendar-year 2015.
Employers. February 2014 payroll tax deposit is due if you're not on a semiweekly deposit schedule.

Monday, March 31
Employers. If you file electronically, send Forms 1098, 1099 or W-2G to the IRS. Otherwise, see Feb. 28 rules. The due date for giving recipients those forms is still Jan. 3I, regardless of whether you file electronically. For information about filing Forms 1098,— 1099 or W-2G electronically, see Publication 1220.

APRIL

Tuesday, April 15
Personal. File your income tax return for 2013 (Form 1040, 1040-A or 1040-EZ) and pay any tax that is due. For an automatic six-month extension, file Form 4868 and pay the projected tax. You can receive an extension by phone if you pay part or all of your estimated income tax that is due with a credit card.
Pay the first installment of your 2014 estimated tax (Form1040-ES).

If you paid cash wages of $1,800 or more in 2013 to a household employee, file Schedule H with Form 1040 and report any employment taxes or tax withheld.
The last day to make 2013 contributions to a regular or Roth IRA.

Make your Keogh plan or Simplified Employee Pension (SEP) contribution for 2013 if you are not requesting a filing extension for your tax return.

File gift-tax returns (Form 709 or 709-A) for gifts made in 2013 that exceeded $14,000 per recipient. For a six-month extension, file Form 4868.
Partnerships (and LLCs treated as partnerships). File your 2013 calendar-year return (Form 1065). Provide each partner with a copy of Schedule K-1, Partner's Share of Income, Deductions, Credits, etc., or a substitute Schedule K-1. For an automatic five-month extension, file Form 7004.
Corporations. Pay the first installment of 2014 estimated income tax. A worksheet (Form 1120-W) is available to help you estimate your tax for the year.
Employers. March 2014 payroll tax deposit is due if you're not on a semiweekly deposit schedule.

Wednesday, April 30
Employers. File Form 941 (payroll tax) for the first quarter of 2014 and deposit any unpaid taxes. Also, deposit unemployment taxes for the first quarter of 2014 if you owe more than S500 in federal unemployment taxes (FUTA) for the year.

MAY

Thursday, May 15
Employers. April 2014 payroll tax deposit is due if you're not on a semiweekly deposit schedule.

JUNE

Monday, June 16
Personal. If you're a U.S. citizen or resident alien living and working (or on military duty) outside the country, send in Form 1040 for 2013 and pay any tax due. See the entry for April 15. File Form 4868 to obtain four additional months to %kw file. (Note: Military participants in combat zones may earn further extensions. See Publication 3, Armed Force? Tax Guide.) Also, individuals should pay the second installment of their 2014 estimated taxes with Form 1040-ES.
Corporations. Pay the second installment of your 2014 estimated income tax.
Employers. May 2014 payroll tax deposit due if you're not on a semiweekly deposit schedule.

JULY

Tuesday, July 15
Employers. June 2014 payroll tax deposit is due if you're not on a semiweekly deposit schedule.

Thursday, July 31
Employers. File Form 941 (payroll tax) for the second quarter of 2014 and deposit any unpaid taxes. Deposit unemployment taxes for the second quarter of 2014 if you owe more than $500 in FUTA for the year. If you maintain an employee pension, profit-sharing or stock bonus plan, file Form 5500 or 5500-EZ for calendar-year 2013. If you use a fiscal year as your plan year, file the form by the last day of the seventh month after the plan year ends.

AUGUST

Friday, Aug. 15
Employers. July 2014 payroll tax deposit is due if you're not on a semiweekly deposit schedule.

SEPTEMBER

Monday, Sept. 15
Personal. Pay the third installment of your 2014 estimated tax. Corporations. If you received a six-month extension from March 17, send in your 2013 calendar-year income tax return (Form 1120 or 1120-A) and pay any tax that is due. Also, pay the third installment of your 2014 estimated income tax.
S corporations. If you received a six-month extension from March 17, send in your 2013 calendar-year income tax return (Form 1120-S).
Partnerships (and LLCs treated as partnerships). File your 2013 calendar-year return if you received a five-month extension from April 15. Provide each partner with a copy of Schedule K-1 (Form 1065).
Employers. August 2014 payroll tax deposit is due if you're not on a semiweekly deposit schedule.

OCTOBER

Wednesday, Oct. 15
Personal. File Form 1040 for 2013 and pay the tax that is due if you received an extension from April 15. This is also the last day to make Keogh or SEP contributions for 2013 if you received an extension.
Employers. September 2014 payroll tax deposit is due if you're not on a semiweekly deposit schedule.

Friday, Oct. 31
Employers. File Form 941 (payroll tax) for the third quarter of 2014 and deposit unpaid taxes. Deposit unemployment tax for the third quarter of 2014 if you owe more than S500 in FUTA for the year.

NOVEMBER

Employers. During November, ask your employees whose withholding allowances will change in 2015 to fill out a new Form W-4. Also, ask each eligible employee who wants to receive advance payments of the earned income credit during 2015 to fill out a Form W-5.

Monday, Nov. 17
Employers. October 2014 payroll tax deposit is due if you're not on a semiweekly deposit schedule.

DECEMBER

Monday, Dec. 15
Corporations. Pay the fourth installment of your 2014 estimated income tax.
Employers. November 2014 payroll tax deposit is due if you're not on a semiweekly deposit schedule.