How difficult is it to become a millionaire?

It's probably not as hard as you might think — if you plan ahead.

David Bach, the author of "Smart Couples Finish Rich," came up with a chart showing how much money people at different ages should set aside each day to save a million dollars at age 65.

Following is a transcript of the video.

Do you want to become a millionaire? Bach says the key is to start investing as early as possible.

To prove how important time is, Bach calculated how much you’ll need to invest each day to save $1 million by 65. Here's a chart showing how much you should save, depending on how old you are when you start.

For simplicity, the calculations assume a 12% annual return and don’t take taxes into account.

So where do you start? Experts recommend to start investing in your 401(k) or Roth IRA.

Bach also advises to refrain from spending on small daily purchases like buying coffee every morning and instead to invest that money. Decades from now, that money will be worth enough for you to buy more than just one coffee.

This video was first published in December 2016.