Most years that means April 15th. This year due to a quirk in the rules savers have until April 18th to make their 2016 IRA contribution. But don’t wait until the last minute. IRA contributions that are credited to your account after the April 18th deadline won’t count towards your 2016 contribution limit. Instead they will be applied to 2017.
Contributions to your Simplified Employee Pension or SEP are different. The deadline for making contributions to your SEP is when you file your taxes up until your tax filing deadline (April 18th) whichever comes first, plus extensions. For some this may mean funding your 2016 SEP as late as October 15th, 2017.
Contribution limits remain unchanged from last year: $5,500 if you are under age 50, and $6,500 if you are age 50 or older. Workers with earned income from their job, small business or self-employment may contribute to retirement plans like IRAs and Roth IRAs.
If you work with a financial advisor do them a favor. Don’t walk into their office on April 18th and expect to make a 2016 IRA contribution. Different IRA custodians have different policies, but some require that monies actually be deposited and posted your account by the tax deadline in order to be considered a previous year contribution. In some cases, a simple postmark dated 04/18/2018 may not be enough.