This article was updated on August 24, 2017, and originally published on February 22, 2016.

Retirement income, including Social Security, is treated differently than wage and investment income for tax purposes. The IRS has its own criteria for taxation of Social Security benefits, and 13 states do as well. Here's an overview of the income tax you may have to pay on your Social Security benefits, and what it could mean to you as a retiree.

Social Security taxes at the federal level

In general, you'll only have to pay federal income taxes on your Social Security benefits if you have a substantial amount of income from other sources, such as wages from a job, income from a business you own, or investment/dividend income.

100 dollar bills scattered on a 1040 tax form.

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When determining how much of your Social Security income may be subject to income tax, the IRS uses your "combined income," which consists of your adjusted gross income (AGI), nontaxable interest, and half of your Social Security benefits.

The actual formula is: Combined income = AGI + nontaxable interest + half of Social Security benefits. For individual (single) tax filers, if your combined income is between $25,000 and $34,000, 50% of your Social Security benefits may be subject to income tax. If your combined income is more than $34,000, up to 85% of your benefits could be taxable.

For joint filers, the income thresholds increase to a range of $32,000 to $44,000 for 50% taxation, and $44,000 and above for 85% taxation. Under no circumstances is more than 85% of your Social Security benefit subject to taxation, no matter how much income you have.

Finally, it's important to note that these income thresholds are current as of the 2016 tax year (the return you file in 2017), and may change for 2017 or subsequent years. However, they aren't indexed to inflation, and they haven't changed since they were initially introduced into legislation.

13 states tax Social Security benefits

In addition to the federal taxes you may have to pay on Social Security benefits, there are 13 states that also tax Social Security. However, the exemptions vary considerably from state to state, so here's a rundown of which states tax benefits, and who has to pay.

State

Social Security taxation

Colorado

The first $20,000 (under 65) or $24,000 (65+) of total retirement income is not taxed.

Connecticut

Benefits are exempt for taxpayers with AGI below $50,000 (single) or $60,000 (married filing jointly).

Kansas

Benefits are exempt for individuals with AGI below $75,000

Minnesota

Benefits are taxable in the same way as the federal level.

Missouri

Benefits are not taxed for AGI under $85,000 (singles) or $100,000 (married), and there is a partial exemption for incomes above this level.

Montana

Montana doesn't tax Social Security benefits for incomes of less than $25,000 (single) and $32,000 (married). However, Montana's income calculation can be different than AGI, so you need to fill out Worksheet VIII of the state's tax return to determine your exemption.

Nebraska

Benefits are taxable in the same way as the federal level.

New Mexico

New Mexico has an overall retirement income exemption of $8,000 per person, subject to income restrictions.

North Dakota

Benefits are taxable in the same way as the federal level.

Rhode Island

Starting in 2016, Social Security benefits are exempt for taxpayers with AGI less than $80,000 (single) and $100,000 (married).

Utah

Benefits are taxable, but individuals can qualify for a retirement income tax credit of up to $450 per person, depending on age and income.

Vermont

Benefits are taxable in the same way as the federal level.

West Virginia

Benefits are taxable in the same way as the federal level.

What it could mean to you

As you can imagine, the amount of income tax you'll have to pay can vary tremendously based on the amount of your Social Security benefits, your other income, and the state you live in.

A retired couple whose only source of income is $30,000 in Social Security wouldn't have to pay taxes at all, but a couple with $30,000 in SS income and $100,000 in AGI who resides in Connecticut would have to pay federal income tax at their marginal tax rate on 85% of their SS income as well as state income taxes.

Consider the big picture

As a final thought, it's important to keep in mind that taxes on Social Security benefits are just one piece of the puzzle. Some states that tax Social Security benefits are actually pretty tax-friendly places to retire, such as Colorado. And, some states that don't tax Social Security at all, like New York and New Jersey, are still among the most taxing places to live. So, be sure to consider the big picture when it comes to the taxes you could face in retirement.