3 self-made millionaires share their No. 1 money-saving trick

Grant of Millennial Money went from broke to seven figures in a few years
Courtesy of Millennial Money

When it comes to building wealth, the formula is simple: save more and spend less. Of course, that's easier said than done.

To help you start saving more, we rounded up tips from self-made millionaires who have socked away lots of money.

From millionaire entertainers to everyday people who felt the need to turn around their financial lives, here are great savers' top strategies.

Simple money habits that will help you build wealth in 2017
Simple money habits that will help you build wealth in 2017

1. Automate everything

In just five years, Grant of Millennial Money went from having $2.26 in his bank account to $1 million. During his five-year journey to seven figures, in addition to focusing on earning, he saved 50% of his income.

The key to saving half your income, Grant says, is to make things automatic: He calls that "essential." He recommends talking to your HR department and having a portion of your income sent to a savings or investment account. This is in addition to contributing to your 401(k), Grant notes.

He's not the only one who advises putting your financial plan on auto-pilot. As self-made millionaire David Bach writes in "The Automatic Millionaire," automating your finances is "the one step that virtually guarantees that you won't fail financially. … You'll never be tempted to skimp on savings because you won't even see the money going directly from your paycheck to your savings accounts."

Grant of Millennial Money
Courtesy of Millennial Money

2. Generate more than one income and save the largest

We can't all be Jay Leno, but we can save like he does. From the moment the comedian entered the working world, he has always had two incomes. "I'd bank one and I'd spend one," Leno tells CNBC. And he made sure to spend the smaller amount.

He kept the habit even after his career took off. When he started hosting NBC's "The Tonight Show," he booked himself at least 150 comedy show gigs a year, "so I never had to touch the principal," Leno says. To this day, he's never spent a dime of his "Tonight Show" money.

Start by thinking about how you can generate more money. Next, employ Leno's strategy: Save the larger form of income and spend the smaller one.

Jay Leno, former host of NBC's "The Tonight Show"
NBC | Getty Images

3. Use the "50-30-20 percent rule"

Kyle Taylor of The Penny Hoarder, who went from cash strapped to self-made millionaire in a matter of years, says one simple formula has helped him save, particularly when dealing with windfalls, like a cash gift or bonus.

It's called the "50-30-20 percent rule." Fifty percent of the money goes straight to the bank — into your checking account, emergency fund, or a long-term savings account — while 30 percent goes towards funding your lifestyle, and 20 percent goes towards fun.

"Having those percentages set up ahead of time will give you the freedom and the control to make sure you're making a wise financial decision," Taylor says.

Kyle Taylor, founder and CEO of The Penny Hoarder
I'm only spending $60 a week for 8 weeks. Here's exactly what I'm buying
I'm only spending $60 a week for 8 weeks. Here's exactly what I'm buying