2011 is flying by, and before you know it we will be ringing in the new year. However, you still have time to save enough funds to max out your 2011 retirement savings account contributions. Here is a look at what you need to know.

Using year-end retirement contributions to lower your taxable income

If you are worried that you are going to owe Uncle Sam a hefty amount of money when it is time to file your tax return, you should know that you have options. You can lower your adjusted gross income (AGI) when you invest into a number of different retirement funds, including a 401(k), a 403(b), or a traditional IRA.

In order for your contributions to count on your 2011 income tax return, they will need to be made to your 401(k) and 403(b) accounts by December 31, 2011. You can make contributions to your IRA accounts up until April 16, 2012, for the 2011 tax year. (April 15 falls on a Sunday.)

A closer look at your 401(k) account

While investing in your 401(k) can lower your taxable income, there are limitations. In 2011, pretax contributions to your 401(k) are limited to $16,500. Note that if you are over the age of 50, you may be eligible for a catch-up contribution, which would raise your overall limit by an additional $5,500. These limits are in addition to any employer contributions. It was recently announced that 401(k) limits will increase in 2012.

A closer look at your 403(b) account

If you have a 403(b) retirement account, you will find that pretax contribution limits are similar to that of a 401(k) account. In 2011, your basic maximum tax-deferred contribution can total up to $16,500. Additionally, you may be eligible to make a catch-up contribution that would also be tax deferred.

A closer look at your traditional IRA account

The rules of the traditional IRA also allow you to make a pretax investment, although limits are lower than with other accounts. As long as you meet income requirements, your contribution if you are under the age of 50 is limited to $5,000 per calendar year. If you are over the age of 50, you are limited to $6,000 per year.

What about Roth IRAs?

If you have a Roth IRA, even though you will pay taxes on your contribution, you should still attempt to max out your allowable contribution for 2011. The amount you are allowed to contribute depends on your age and your AGI.

As long as you meet income requirements and are under the age of 50, you can contribute a total of $5,000 to your account in 2011. Those over the age of 50 and within income limits can contribute $6,000. If you have reached age 70½, you are no longer eligible to make contributions to a Roth IRA.

Like traditional IRAs, year-end contributions to Roth IRAs can be made up until April 16, 2012. It is important to note that if you have more than one IRA account, your maximum year-end contribution for all IRA accounts cannot exceed $5,000 if you are age 50 or under and $6,000 if you are over 50. Inn other words, you cannot invest $5,000 into each account—you can invest $5,000 total between all of your IRA accounts.

Jeff Rose is an Illinois Certified Financial Planner. He blogs at Good Financial Cents and Soldier of Finance. He loves Crossfit workouts, writes about Roth IRA rules and craves In-N-Out burger. You can follow his updates on Twitter.