45 / 180 Day Calculator This 45 / 180 day calculator determines your 1031 exchange deadlines for you. JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember 12345678910111213141516171819202122232425262728293031 2016201720182019202020212022 Initial sale date: 45 day identification period ends: 180 day purchase date ends: