You can choose when and how much you contribute to a Roth IRA, and you can change your contribution amount as often as you like. If you don’t contribute at all, you will never get the money back.

Your contribution will be deducted from your paycheck and your money will be distributed tax-free to your Roth IRA after you die (you can use a roth ira calculator to figure our the exact deduction). For simplicity, it’s best to set a limit on your annual contributions. That way, you can’t contribute more than what you actually need.

Here’s how you contribute:

Start by using an online contribution tool. It helps to know that, starting in 2017, you can contribute up to the annual contribution limit for 2018, plus the amount by which you’ve overpaid taxes in 2017. That can be $6,500 if you’re 50 or older or $5,500 if you’re under 50.

Step 1: Calculate your contribution amount for 2018. This assumes you’re over the limit for each year of the year you want to contribute and the taxes you owe. (In case you don’t know that: In 2018, you have a 10 percent tax bracket and no income tax.)

(In 2018, you have a 10 percent tax bracket and no income tax.) Use the IRS’ tax-free contribution limit calculator on the site to work out your contribution.

of the year you want to contribute and the taxes you owe. (In case you don’t know that: In 2018, you have a 10 percent tax bracket and no income tax.) Your plan contributions are taken into account. So if you contribute $10,000 in 2018, the money is taken out of your Roth IRA to give to your employer. Of course, if your employer gives you an employer match, the money is likely in your 401(k) or other employer-sponsored plan, so you’d want to leave that in there as well.

The big caveat here is that you need to plan ahead. You don’t want to contribute at a time when you’ll be in a lower tax bracket, and your employer match can’t be part of a catch-up contribution for the current year.

What is a Catch-Up Contribution?

A catch-up contribution is one that follows you into retirement. This is done by making contributions to your traditional IRA, Roth IRA, 401(k) plan, or other employer plan. You don’t have to start a catch-up contribution until you reach age 70, but you don’t have to stop until you reach age 59 either. For instance, if you’re age 58 when you take your first traditional IRA contribution and you contribute another $3,000 (later than your traditional IRA contribution limit), you’ll have already contributed $8,000 into your IRA. That’s a total of $24,000, or a 75% catch-up contribution. How the Catch-Up Contribution Works The catch-up contribution is calculated by taking your regular salary and dividing it by your 401(k) plan’s salary limit. The catch-up contribution for 2014 is $55 per paycheck (for a full-time employee). There is no catch-up contribution for non-full-time employees. It’s not a catch-up contribution for your spouse. To find out how much of your salary you’ll contribute to your 401(k) plan each year, go to IRS.gov/401(k).