Your last 2015 quarterly estimated tax payment is due by January 15, 2016.
Important: If you plan to take this payment as a deduction on your 2015 federal income tax return, you must make the payment by December 31, 2015.
If you are self-employed or have other fourth-quarter income that requires you to pay quarterly estimated taxes, get them postmarked by January 15, 2016.
Estimated tax is the method used to pay tax on income that is not subject to withholding. This includes income from self-employment, interest, dividends, alimony, rent, gains from the sale of assets, prizes and awards. You also may have to pay estimated tax if the amount of income tax being withheld from your salary, pension, or other income is not enough.
If you do not pay enough through withholding or estimated tax payments, you may be charged a penalty. If you do not pay enough by the due date of each payment period you may be charged a penalty even if you are due a refund when you file your tax return.
More information on IRS.gov
Publication 505 (2015), Tax Withholding and Estimated Tax
