You’re not alone if terms like 401(k) and IRA sound confusing. Turns out, many Americans’ knowledge of retirement-related topics doesn’t quite make the grade.

According to a new study by TD Ameritrade, a significant number of Americans don’t know basic facts about how to save for retirement. For instance, only one of out five people knows what the 401(k) contribution limit is for 2019.

“If you’re not financially literate, you’re leaving money on the table,” says Christine Russell, senior manager of retirement and annuities at TD Ameritrade. “We have these powerful tools like 401(k)s and IRAs that can help build retirement savings, but…sometimes people are not taking advantage of the true financial benefits that they are due.”

The good news is that it’s never too late to start. Learning about the most effective ways to save and grow your retirement funds through vehicles like 401(k)s (employer-sponsored retirement savings accounts) and IRAs (individual retirement accounts) will help boost your account balance no matter what your age (See, you already know more than you did a few minutes ago!)

Test your retirement planning knowledge with the questions below:

What is the 401(k) Contribution Limit for 2019?

Survey question: What’s the contribution limit for employees who participate in a 401(k) in 2019 (excluding the catch-up contributions allowed for those age 50 and over)?

Correct answer: $19,000

Answered correctly: 19%

It’s always a good idea to max out your retirement accounts if you can afford to (or contribute as much as you can within your budget). More Americans than ever have 401(k )retirement savings plan these days, thanks to a rise in the number of companies that auto-enroll employees when they start a job, but the default savings rates most people are automatically signed up for are far too-low — the average is around 3% of your pay— to meaningfully save for retirement.

At the very least, you should always be contributing the minimum amount to meet your employer’s match, which is about 4.1% on average, according to Fidelity. If you don’t, you’re basically giving up free money.

“You need to be contributing to your 401(k) at least enough to get the match, because no one is going to give you that money after the fact,” explains Russell. “If this year I don’t contribute the max to get the match, but next year I contribute even more, they’re not going to go back and give me the extra match because I missed out on it this year. It’s use it or lose it when it comes to 401(k) match.”

What is the IRA Contribution Limit for 2019?

Survey question: What’s the 2019 limit on the annual contributions to a traditional IRA (excluding catch-up contributions)?

Correct answer: $6,000

Answered correctly: 35%

IRAs offer an alternative way to save for retirement in addition to (or in place of) a 401(k). IRAs differ from 401(k)s because they are not connected to your employer, and you can open one on your own. Make sure you understand the difference between the numerous kinds of IRAs.

Unlike a traditional IRA, a ROTH IRA is not tax-deferred–meaning, you pay taxes to Uncle Sam up front on your contributions, which is a good option if you’re currently in a lower tax bracket than you think you will be when you retire. If you’re self-employed, you can contribute to a SEP (simplified employee pension) IRA.

Can nonworking spouses contribute to an IRA?

Survey question: True or False: Nonworking (or low income-earning) spouses can contribute to a traditional IRA.

Correct answer: True

Answered correctly: 26%

Nonworking spouses can contribute to both a traditional IRA and a Roth IRA as long as the married couple files a joint tax return and each has a separate IRA. The contribution limits for the nonworking spouse are the same ($6,000 for 2019 for those under 50). But keep in mind that both spouse’s IRA contributions either can’t exceed your joint taxable income or the yearly IRA contribution limit times two (whichever is less). If your income is above a certain threshold, your IRA contributions may not be entirely tax deductible so make sure to factor that in.

Setting up an IRA for a nonworking spouse is important to ensuring that the partner who doesn’t work does not end up with no retirement savings, says Russell.

If you open an IRA, “no matter what might happen in the future with that relationship, that’s going to be money for the nonworking spouse,” she says.

Do you have to be in a certain tax bracket to contribute to an IRA?

Survey question: True or False: You don’t need to be in a certain tax bracket to qualify for contributing to a traditional IRA.

Correct answer: True

Answered correctly: 40%

It doesn’t matter what tax bracket you are in when it comes to contributing to an IRA. Anyone at anyone income level can contribute to a traditional IRA, though there are restrictions on how much of your contributions are tax deductible if your income exceeds certain limits. (Roth IRAs, on the other hand, have income limits for contributions.) The IRA income thresholds are different for people who are covered by a employer sponsored retirement plan and those who are not.

It’s a common misconception that you can’t contribute to an IRA if you have a 401(k) plan at work, says Russell, but that’s not true when it comes to traditional IRAs.

“With a traditional IRA you can still contribute even if you’re in the 401(k) at work,” she says. “Your tax break on the IRA might be a little different, but you’re still going to be able to contribute, and at the very minimum get tax-deferred income that you’re not going to be taxed on until retirement.”

What is the deadline to contribute to your 2018 IRA?

Survey question: What is the deadline to contribute to your 2018 IRA (Individual Retirement Account)?

Correct answer: April 15

Answered correctly: 22%

You can still retroactively contribute to your IRA for 2108 until April 15th of this year, which could offer you the added benefit of a lower tax bill, especially if your contribution drops you into a lower tax bracket. To help determine if putting money in an IRA will change your tax bracket, double check this year’s new tax brackets created by the Tax Cuts and Jobs Act. Lower-income tax filers can also take advantage of the saver’s credit.