Need more time to prepare your tax return? File your request for a tax extension by April 18 to push your tax deadline back to October 16, 2018.
If you haven't already funded your retirement account for 2017, do so by April 18, 2018. That's the deadline for a contribution to a traditional IRA, deductible or not, and a Roth IRA. However, if you have a Keogh or SEP and you get a filing extension to October 17, 2018, you can wait until then to put 2017 money into those accounts.