In most jurisdictions for tax purposes, you are considered divorced for the entire year if you are divorced on or before December 31 . You are considered married for the tax year if married on Dec. 31. Therefore, for the tax year in which you divorce, you must file separate federal and state tax returns. You cannot file jointly for the tax year in which you divorce.
Many divorcing couples delay having the divorce finalized at this time of the year because there is usually a financial benefit to filing a joint, married return. You can file a married, filing separately return if you find there is a tax advantage to doing so.
If you file for divorce towards the end of the calendar year and do not wish for the divorce to become final during that calendar year, you should make it clear to the clerk of the divorce court in which you are filing that you DO NOT want the final judgment or decree of divorce to be entered during the current calendar year. They should put a note on the file to this effect.
On our online divorce site, OurDivorceAgreement.com, the Property Settlemment Agreement document has language that confirms that you will be filing separately in the year of the divorce because you cannot file as married if divorced during the tax year, as explained above.
(By all means, consult your tax advisor for advice pertaining to your precise situation and please do not consider any information contained here to be legal advice.)