Every investor dreams of building a million dollar project nest egg for retirementbut some simply reject the idea that they could ever save that much, thinking it’s impossible — and that’s unfortunate, because for most Americans, that’s simply not the case.

Learn more: How to Turn $100,000 into a Million: Your Step-by-Step Guide

Check: 5A subtle genius moves all the rich people who earn with their money

One of the most important elements of building a seven-figure portfolio is something every investor starts with: time. The other, which may require some expert advice, is investment returns. But given enough time, compound interest can exceed even moderate investment returns, and build a million dollar portfolio.

The power of compound interest

The power of time over the market is quite astonishing when seen in black and white. But to get the biggest gains that compound interest can offer, investors may have to wait decades, which can be difficult to do, especially for those new to investing.

But it’s worth thinking about to understand how relatively simple it can be to build a million-dollar portfolio, if you get decent market returns and start as early as possible.

Imagine a 20-year-old investor who wants to retire at age 65, which is actually two years before the Social Security Administration pays you your full benefits. Earning a relatively modest average annual return of 6%, this investor will only have to pay around $363 per month to reach a $1 million portfolio. If he could instead earn the 10% that the stock market returns each year over the long term, the required monthly savings amount would drop to a miniscule $96.

But even if an investor waits until age 30, retiring with $1 million at age 65 is still very feasible. With an average annual rate of return of 6%, this would require saving $702 per month – but if an investor can earn 10% per year, that amount drops to a paltry $264.

These examples show that investing for decades can yield huge returns in terms of compound interest. But it’s also undeniable that the higher an investor’s return, the easier it will be for them to achieve a million-dollar portfolio.

Try this: How to Get a 10% Return on Investment (ROI): 10 Proven Methods

How to improve returns on investment

So what are the best ways to improve investment returns? If you believe one of the world’s most successful investors, Berkshire Hathaway CEO Warren Buffett, just put your money in a low-cost index fund. As the famous billionaire said CNBC in 2017, his best advice to the average investor is to “always buy a low-cost S&P 500 index fund.” I think it’s the thing that makes the most sense almost all the time.

Buffett made this statement because there is evidence that most investors, even professional investors, cannot consistently beat the overall return of the stock market.

On the one hand, it’s difficult to consistently select stocks, year after year, that outperform the market’s fairly impressive 10% average annual return. But the low cost of index funds also makes it easier for them to outperform actively managed accounts because their returns aren’t held back by high fees.

How to Stick to a Consistent Investing Schedule

Of course, it’s one thing to chart a path to $1 million and another to actually do it. Although relatively small savings amounts can grow to seven-figure values ​​over time, the process only works if investments are made consistently.

The best way to never miss a monthly contribution is to automate transfers from a bank account to an investment account. Then, no matter what happens in the market or in an investor’s personal financial life, that money is automatically invested.

To have an even better chance of reaching that million-dollar high, it’s also a good idea to increase contributions based on income. Most workers earn more in their 30s than in their 20s, and in their 40s than in their 30s, and so on. It is therefore a good strategy to increase contribution levels as income increases.

Contributing extra money, such as gifts, tax refunds, or end-of-year bonuses, is another good way to increase the value of your account without taking on an additional financial burden.

More from GOBankingRates

This article was originally published on GOBankingRates.com: 3 Wealth Management Tips for a $1 Million Portfolio