The 2027 tax calendar
The dates that matter for the 2026 return and the 2027 tax year, federal and Colorado, in one place. Booklet page 62.
| Jan 15 | Fourth-quarter 2026 estimated payment due (federal and Colorado) |
| Jan 31 | Employers’ and payers’ deadline to send W-2s and most 1099s; brokerage 1099s usually come in mid-February |
| Mid-Feb | Earliest refunds for returns claiming the earned income credit or the additional child tax credit; the PATH Act holds them until then, even if filed in January |
| March | IRS usually publishes its Dirty Dozen list of the year’s tax scams (verify) |
| Apr 15 | 2026 federal and Colorado returns due, and any balance owed. Extension requests due (an extension gives time to file, not time to pay) |
| Apr 15 | First-quarter 2027 estimated payment due |
| Apr 15 | Last day to make a 2026 IRA or HSA contribution |
| Apr 15 | Colorado: extension to October 15 is automatic if at least 90% of the tax is paid by April 15 (verify) |
| Jun 15 | Second-quarter 2027 estimated payment due |
| Sep 15 | Third-quarter 2027 estimated payment due |
| Oct 15 | Extended 2026 returns due, federal and Colorado |
| Oct 15 | Medicare open enrollment, October 15 to December 7; 2028 IRMAA premiums will be based on your 2026 return |
| Oct–Nov | IRS announces inflation-adjusted figures for 2028: brackets, standard deduction, retirement limits |
| Dec 31 | Last day for 2027: required minimum distributions, charitable gifts (including from an IRA), Roth conversions, and anything else that has to happen in the tax year |
| Jan 15, 2028 | Fourth-quarter 2027 estimated payment due |
Behind the scenes
The first week of February is when a preparer’s own calendar fills up. The software updates arrive almost daily as the IRS finalizes forms; a return prepared on February 2 may need a form that isn’t approved for e-filing until the 10th. Brokerage 1099s are still weeks away, so early appointments are mostly W-2 households. And the clients who come first are often the ones expecting the largest refunds, which means explaining the mid-February PATH Act hold, again, to people who filed on the first day for exactly that reason.