If you're in your 30s and don't have much saved for retirement, you're not alone.

As of the fourth quarter of 2023, the median 401(k) balance for account holders in their 30s was around $20,400, according to data from Fidelity Investments, the nation's largest 401(k) provider.

That's a far cry from the $1.46 million the average American thinks they'll need to save in order to retire comfortably, according to Northwestern Mutual's 2024 Planning and Progress study.

But don't panic. Even if you have little or no retirement savings, you can still get back on track — and even retire as a millionaire. You just may need to set aside a bit more money each month than if you'd started earlier.

CNBC calculated how much you could retire with if you contributed $1,000 a month to a retirement investment starting at ages 25, 30 and 35. These calculations assume a starting balance of $0 and an annual rate of return of 6% or 8% until age 65. Additionally, the calculations don't account for unpredictable events like market volatility.

If you start at 25

• Earning a 6% annual rate of return: $2,001,448
• Earning an 8% annual rate of return: $3,514,281

If you start at 30

• Earning a 6% annual rate of return: $1,431,834
• Earning an 8% annual rate of return: $2,306,175

If you start at 35

• Earning a 6% annual rate of return: $1,009,538
• Earning an 8% annual rate of return: $1,500,295

As you can see in the calculations, the sooner you can start saving for retirement, the better. That's because you give your contributions a longer amount of time to grow through the power of compound interest.

But try not to focus solely on your account balance at any given time, since it can be impacted by factors beyond your control, such as market volatility.

Instead, financial experts typically recommend focusing on your savings rate, which is the percentage of your annual income you're contributing toward your retirement accounts, such as a 401(k). Fidelity recommends aiming for a savings rate of 15%, including any matching contributions from your employer.

And remember, it's OK to start small and work your way up.

"You've got plenty of time, you're just gonna have to end up in a slightly more aggressive savings rate than you would have if you started earlier. And that's fine," Anne Lester, a retirement expert and author of "Your Best Financial Life: Save Smart Now for the Future You Want," told CNBC in March.

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