Millionaire status was once reserved only for the rich and famous, but these days, you might need to have at least a million dollars in the bank to retire comfortably.

Retirement is more expensive than ever, and the average American age 65 and up spends around $46,000 per year, according to the Bureau of Labor Statistics. If you spend that much every year for 25 years, you'll spend a total of around $1.15 million -- and that's not even considering the effects of inflation.

Jar full of hundred-dollar bills.

Image source: Getty Images.

Fortunately, it's not as challenging as you may think to retire a millionaire, even if you're earning an average salary. Just follow these four steps.

1. Calculate how much you'll need to save each month

If $1 million is your ultimate retirement goal, figure out how much you should be saving every month to reach that goal by retirement age.

Two factors that affect this are your current age and your desired retirement age. The fewer years you have to save, the more you'll need to save each month. While you can't change your current age, you might choose to delay retirement by a few years to make it a little easier to reach your saving goal.

For example, say you're 35 years old with nothing saved for retirement, and you want to retire with $1 million by age 65. Using a compound interest calculator, we find you'll need to save around $900 per month to have $1 million saved by age 65, assuming you're earning a 7% annual rate of return on your investments. However, if you were to delay retirement until age 70, you'd only need to save around $650 per month to reach that $1 million goal.

2. Be prepared to make some serious sacrifices

Retiring with $1 million isn't easy, but it's more challenging if you're closing in on retirement age or have little to nothing saved already. You might even need to save thousands of dollars per month if you're only a decade or two away from retirement with next to nothing in your retirement fund.

That's simply not achievable for some people, but if you're willing to make sacrifices, it could put your goal within reach. If money is tight and you've determined that you'll need to start saving several hundred dollars per month, begin by taking an honest look at your budget and making some cuts.

Depending on how serious you are about retiring a millionaire, you might need to eliminate all but the most crucial monthly expenses. Start by cutting truly unnecessary expenses including any subscriptions or memberships you rarely use. Next, trim down the nice-to-have costs, like dining out, cable, going to the movies, and shopping for things you don't need.

Finally, if you're still struggling to come up with enough cash, take a look at your biggest expenses and see if there are ways those can be reduced. For instance, are you willing to sell your car? What about downsizing your home to save money on your mortgage? These are major lifestyle changes, but they can help you save hundreds more per month.

3. Invest in the stock market

It's one thing to come up with the money you need to save each month to reach your goal. But if you're not investing it in the right places, you'll probably come up short.

Some people may think it's smarter to invest their savings in "safe" investments, like a money market fund, a CD, or even a savings account. These types of investment options carry less risk, sure. But they also have much lower potential rates of return, so your money won't go very far. If you invest $900 per month in an account earning a 3% annual rate of return, for instance, you'll only have around $513,000 saved after 30 years -- nowhere near your $1 million goal.

The stock market may seem scary, but it's the most effective way to earn high enough returns to save a significant amount of cash by retirement age. The key is to make smart investment choices to protect your money.

Index funds and mutual funds allow you to spread your money over dozens or even hundreds of different stocks, limiting your risk in the event that one or two companies within the fund take a nosedive. While the stock market will always experience ups and downs, over time, you can expect to see an upward trend in your earnings.

4. Check in on your savings regularly and make adjustments

With any goal, it's important to check in on your progress regularly and see where you stand. If you're behind where you thought you'd be, you might need to make some adjustments to get back on track.

It's tough to tell whether you're on track for retirement simply by looking at your total savings. Because of compound interest, it may not seem as if you're making much progress within the first few years, but your savings will grow exponentially after a few decades. If you're making smart investment choices and meeting your monthly saving goals, don't fret if your investments haven't grown as much as you think they should -- it takes time to see dramatic results.

The things to think about as you're giving your savings a checkup include factors like whether you've been saving as much as you should each month and if your long-term goals are the same as when you began saving. If you've skipped saving for a few months or saved less than you should, you might need to start saving more each month to make up for it. Or if you have reason to believe you might not be able to work as long as you'd initially planned, you may have to boost your savings now in case you're forced into retirement earlier than you expected.

Retiring a millionaire isn't easy, but it is achievable if you're willing to work for it. The sooner you get started saving, the easier it will be.