Editors' pick: Originally published Nov. 17.

If there's a widely held - but false - belief about Social Security, it is that the monthly check (the average amount is $1,341, and the  maximum amount is about $3,576) is tax free. Don't tell that to the 40% of beneficiaries who pay federal income tax on the check. There's even a special IRS publication devoted to the Social Security tax bite.

Additionally, 13 states tax Social Security: Colorado, Connecticut, Kansas, Minnesota, Missouri, Montana, Nebraska, New Mexico, North Dakota, Rhode Island, Utah, Vermont and West Virginia.

Don't think you don't have to file an IRS return because you collect Social Security. If it's your only income - 43% of singles use Social Security for 90% of their income - you in fact don't have to file. But when other income enters the picture - if you earned more than $11,850 in the most recent tax year - you do.

The question is: how to avoid paying income tax on the monthly Social Security check? The easy part of the answer is live in one of the 37 states plus the District of Columbia where Social Securityis not subject to income tax.

The harder part is finding ways to duck the federal levee - which may kick in on as little "combined income" as $25,000 for an individual and $32,000 for a couple. Understand, however, that experts are ready with pointers that may well legally minimize, even eliminate federal income tax on Social Security.

The starting point is that "combined income" the IRS uses to determine tax. The term means your adjusted gross income plus nontaxable interest plus one-half your Social Security benefit. Note: tax exempt interest must be cranked into this calculation.

As much as 85% of the Social Security benefit may be taxed - if your combined income is more than $34,000 as an individual or $44,000 as a couple. Earn $25,000 to $34,000 as an individual or $32,000 to $44,000 as a couple and you pay income tax on up to 50% of your Social Security benefit.

The calculations can get complex. There also are unexpected footnotes to the tax code, such as treaties that allow U.S. citizens who are residents of a handful of countries - including Ireland, Canada and Israel - to avoid pay U.S. income tax on their Social Security check.

So, how to lessen your tax burden?

Convert into Roth IRAs is advice from Mathew Dahlberg, a certified financial planner with Mainstreet Investments. You ideally want to do this conversion of traditional IRAs into Roth before you retire but the benefit is that monies pulled out of a Roth do not add to combined income. From a traditional IRA, the monies do count and that's why they become a tax albatross to some retirees.

Ditching traditional, so-called tax advantaged IRAs in favor of Roth IRAs is the single most commonly mentioned tactic by financial planners. Dahlberg added: "with our clients that are close to retirement we run scenarios to determine if converting those pre-tax IRAs to a Roth IRA will save money in taxes on a gross basis, since conversions are taxable in the year in which they take place."

A variation, recommended by some advisers, is to just cash out traditional IRAs - there's no penalty if you are at least 59.5 - before collecting Social Security. Park the cash in a non-income producing asset. That won't affect your combined income once you begin to collect Social Security.

Look at ways to reduce Adjusted Gross Income, said certified financial planner Brian Vosberg, author of The Complete Retiree's Guide to Social Security. Remember, there are three pieces to the "combined income" formula: Adjusted Gross Income, Social Security, non-taxable interest income. Attacking AGI - by lowering the amount earned or upping deductions - can move combined income from the high tax bracket to the lower or maybe even out of taxation completely.

Also, before taking Social Security, do the math on its tax impacts. Will deferring collection by, say, two years past full retirement age - increasing the check earned by 16% - nudge you into the taxable zone? If so, maybe the deferral isn't the wise move and earlier collection is.

Sell your muni bonds, advised certified financial planner Damon Gonzalez with Domestique Capital, who particularly urged doing it if your portfolio has municipal bonds paying a low rate of interest ("many pay less interest than a mortgage," said Gonzalez) and you in fact also are paying on a home mortgage (one-third of seniors are). The back story: the interest paid on a muni bond counts towards the "combined income," so getting rid of it to reduce expenses is a potentially shrewd move.

Confused? You have every right to be. This is a math of multiple variables - the IRS publication includes worksheets. But even experts said that this gets complicated fast. If in doubt, don't be embarrassed to seek out help - many organizations offer free tax advice to retirees.

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