45 / 180 Day Calculator Fill out the below form to calculate your 45 day and 180 day time frames. JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember 12345678910111213141516171819202122232425262728293031 2016201720182019202020212022 Initial sale date: 45 day identification period ends: 180 day purchase date ends: