You can still boost your 2010 IRA contribution

Mason jar with pennies spilling out

Money added to IRAs through April 15 can count against your 2010 contribution limits and taxes.

Most savers are eligible to contribute $5,000 to their individual retirement account for 2010 -- $6,000 if you're over 50.

But how much you make can reduce how much of your contribution to a traditional IRA can be deducted from your taxes.

So can your participation in other tax-deferred retirement programs, primarily 401(k) plans, offered by your employer.

Income also matters with a Roth IRA. Savers with higher incomes are allowed to contribute less than the maximum to Roth IRAs. Those with very high incomes cannot contribute at all.

The rules also change from year to year, so the contributions you were allowed to make in 2009 may not be the same for 2010.

Here's a quick rundown of how much you can contribute, and deduct, for 2010:

Traditional IRAs

If you are under age 50, the maximum contribution is $5,000 or your entire taxable compensation for the year, whichever is less.

You can split this amount between a traditional IRA and a Roth IRA.

If you're 50 or older, you can make an additional contribution of $1,000.

There is no income restriction on contributions to traditional IRAs.

No matter how much you make, you can still add the full $5,000 to $6,000 to your account. That holds true for each spouse of a married couple filing jointly.

But how much you make, and whether you participate in a 401(k) retirement plan where you work, can reduce the amount of your contribution that can be deducted from your taxable income.

That's important because being able to deduct contributions, and lower your current tax bill, is a major benefit of traditional IRAs.

If you do contribute to a 401(k) plan, the income guidelines for deductibility depend on your tax-filing status.

For singles or heads of households, your contribution is:

For couples filing jointly, your contribution is:

Savers who do not contribute to a 401(k) plan at work must follow a different set of rules.

Your contribution is fully deductible, regardless of income, if you're single or a head of a household or married and filing jointly.

Married couples with one spouse participating in a 401(k) plan can:

Roth IRAs

If you are under age 50, the maximum contribution is $5,000 or your entire taxable compensation for the year, whichever is less.

You can split this amount between a traditional IRA and a Roth IRA.

If you're 50 or older, you can make an additional contribution of $1,000.

Those rules apply individually to each spouse for a married couple filing jointly.

Contributions to Roth IRAs are made with after-tax dollars, so none of it is tax deductible.

But allowable contributions decrease as income goes up.

If you're single or the head of a household, you can make a:

If you're married and filing jointly, you can make a:

The obvious challenge in all of this: You can't really know your modified adjusted gross income until the year is over and you prepare your 2010 tax return.

Modified adjusted gross income starts with adjusted gross income and adds back a few other items, such as the deduction for student loan interest and the deduction for a regular IRA contribution.

IRS Publication 590 has worksheets that can help you figure out your adjusted gross income and how much you can contribute to a Roth or whether contributions to a traditional IRA are deductible.

Follow Interest.com on Twitter.