The US tax year runs from 1 January to 31 December.
The return must be submitted to the IRS by April 15th following the end of the tax year. An automatic 2 month extension to June 15th is given to individuals who are living outside of the United States and a further 4 months extension to October 15th can also be granted to those living outside the US provided the appropriate extension request is submitted to the IRS prior to the normal filing deadline.
Payment of any US tax liability is due by April 15th following the end of the tax year. This date cannot be extended even if applying for extensions of time to file the return and interest and penalties will be charged from this date until payment is made.