With the decline in pensions and Social Security losing buying power, 401(k)s have become an increasingly important part of retirement planning. It's where many workers keep most of their savings, and it also gives them a chance to earn an employer match on those savings so they don't have to do it all alone.

Yet, many people aren't able to save as much as they'd like to in their 401(k)s. Many don't save anything during the early years of their career. But it might still be possible to catch up. Here's a look at how long it would take you to save the average 401(k) balance if you're starting from zero.

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You could reach the average in as little as eight years

The average 401(k) balance was $134,128 in 2024, according to Vanguard's "How America Saves" report. However, the median balance -- a better representation of what the typical American has -- is just $35,286.

You may feel worried if you're behind on these numbers, but it might be possible to catch up. How quickly you can do this depends on how much you can set aside each month and what kind of return you earn on your savings.

The table outlines how many years it would take you to save the $134,128 average balance based on various contribution rates and average annual returns:

Data source: Author's personal calculations. All answers rounded up to the nearest year.

This data reveals a few things. First, as you might expect, the larger your contributions, the faster you reach your savings goal. If you can make larger contributions, you stand a better chance of not only meeting, but surpassing the average 401(k) balance.

We also see the value of investing, especially over the long term. You might notice that the difference between a 6% and an 8% average annual rate of return is 11 years for those who contribute just $20 per month to their 401(k)s, but it makes virtually no difference for those contributing $1,000 per month.

That's because those saving $1,000 per month reach the $134,128 goal primarily through their personal contributions. By the end of nine years, their money hasn't been invested long enough to generate significant investment returns. However, over a long period, as we see with those contributing $20 per month, a larger investment return makes a significant difference because your balance is made up of a lot more earnings.

This information doesn't count 401(k) matches. If you qualify for one, you could reach the average 401(k) balance sooner than the years shown in the table.

The average is a good start, but it probably won't be enough

You should feel proud about saving the average 401(k) balance because it's a feat many don't accomplish. But at the same time, you shouldn't rest on your laurels once you get there. For most people, retirement will cost upwards of $1 million or maybe even $2 million. Your Social Security benefits will cover some of this, but you'll need to fund the bulk of it yourself.

Looking at the table, it may be tempting to bank on high investment earnings, but this isn't wise. You could earn a high rate of return on your investments, but if you don't, you could wind up with far less than what you need. It's much better to be too conservative in your investment return estimates than too optimistic.

If you haven't already done so, it's worth estimating how much your retirement will cost you. This is a more useful goal to aim for than an average that includes people of all ages and backgrounds, who likely have different retirement goals than you.

You might not be able to save as much as you want or feel you need to right now. In that case, start with what you're able to set aside. Even small contributions add up over time, as we saw.

You may also need to rethink your retirement timeline. Delaying retirement or slowly decreasing your hours rather than retiring suddenly could help you reduce your retirement costs without putting a greater strain on your finances today.