Tucked into the federal tax code are some tax benefits pegged to specific levels of income, and knowing what those income numbers are can potentially lead to some tax savings.

Even though it’s too late for most changes a person might make to their taxable income or allowable deductions for 2014, sometimes a modest contribution to an IRA is all it takes to pull taxable income below the limit where an extra tax benefit will kick in.

Some federal tax credits get incrementally smaller as your income rises, such as the Child and Dependent Care Credit. Others fade away slowly after your income exceeds a certain limit, such as the Child Tax Credit.

And still others drop sharply or disappear entirely if your income is just a dollar more than a specific income threshold. Those are the ones that require careful attention, if your income is in the range where you might qualify.

The best examples are the Earned Income Tax Credit and the Saver’s Credit.

The Earned Income Tax Credit rules are complex but the three main criteria depend upon filing status, such as single or married filing a joint return, and taxable income, and how many dependent children (if any) are in the household. The credit is meant to help working people with lower incomes, and the maximum income limits are the important numbers to be aware of.

For example, a single parent with one child can claim the credit for 2014 if their adjusted gross income is not a penny more than $38,511 (the limit is $43,941 for a married couple with one child). The credit can be worth several thousand dollars.

So, what do you do if you’re that single parent and your adjusted gross income is $39,000. The EITC would be just out of reach. However, bring that adjusted gross income down by making a $500 tax-deductible IRA contribution for 2014, and suddenly that person qualifies for a credit potentially worth thousands of dollars.

To see all the rules and income cut-offs, go online and find IRS Publication 596.

The Saver’s Credit is a tax credit for people who contributed to a retirement plan such as an IRA or 401k, and who don’t earn too much money to claim the credit.

A married couple can have an adjusted gross income as high as $60,000 and still qualify for the Saver’s Credit, which is a percentage (from 10 percent to 50 percent) of up to $2,000 in retirement contributions per filer. For example, if a married couple with an AGI of $60,000 each contributed $2,000 to a retirement plan for 2014, they qualify for a 10 percent credit, a total of $400.

Note that if one spouse contributed $4,000 and the other contributed nothing, the tax credit would be just $200, because it applies to only the first $2,000 for an individual or the first $2,000 for each spouse filing jointly.

Now, here’s the key point to remember. Imagine that same couple figures out their taxes — it’s hard to know your exact “adjusted gross income” until you do — and they are just over the threshold for the Saver’s Credit. Let’s say their AGI is $60,500.

Well, as with the EITC example, if they were to contribute another $500 to an tax-deductible traditional IRA for 2014, which is allowed up until April 15, that would reduce their AGI enough to claim the Saver’s Credit that in my example would be worth $400 to them. So, contribute an extra $500 to retirement savings and get $400 back; a no-brainer.

That’s not such an unlikely scenario. I know, because I had a similar experience with my own taxes some years ago. The thing is, a software program, and even an accountant, may not point out that you are over an income threshold for a tax credit but could change that by contributing to a traditional IRA.

The income limits for the Saver’s Credit depend on filing status; married/jointly, single or head of household. The size of the credit then depends on income.

For a married couple, it’s a 10 percent credit with an AGI of $39,001 to $60,000, a 20 percent credit with an AGI between $36,001 and $39,000, and a whopping 50 percent credit for an AGI of $36,000 or less.

A single person would have to earn $30,000 or less to claim the credit, but a “head of household” (such as a single parent) could earn up to $45,000.

For more details, go online to IRS.gov and find “Retirement Topics — Retirement Savings Contributions Credit.”

Remember that “adjusted gross income” is lower than what most people think of as their annual income, so some of these income limits are higher than they may sound. Contributions to a tax-deductible IRA reduce one’s AGI, which is why the scenario I described earlier works.

Of course, the lower one’s income, the harder it is to find money to set aside for retirement, but that’s the point of the Saver’s Credit. It’s an incentive to save.

To claim the Saver’s Credit, a person must be at least 18 years old, not a full-time student, and not claimed as a dependent on someone else’s tax return.