<prompt> Human: I did my tax returns and figured out that I owe 13k in taxes. Should I file my returns in February or the day of the deadline in April? If the penalties and interest payment stay the same through the deadline, it would make more sense to file late as I can earn interest on that money for a couple of months. If the interest is calculated through April, then it makes more sense to pay that in February to avoid additional interest payments.  <response>: File your return as soon as you know it is complete and correct, no later than 4172018.Pay your tax liability no later than 4172018 to avoid the Failure To Pay penalty and interest. 