Common 401k Mistakes and How to Avoid Them

Everyone · Mistakes to avoid · Updated October 1, 2026 · LearnLife Editorial

Why Do People Make 401k Mistakes?

Many 401k mistakes stem from a lack of understanding about how these retirement plans work, limited financial education, or simple procrastination. Some people delay enrolling because they think retirement is far away, while others underestimate the impact of compounding growth by contributing too little. Others might make emotional decisions, like cashing out in a financial pinch, without realizing the long-term costs. Additionally, confusion about rules around rollovers, withdrawals, and beneficiary designations can lead to errors. Overcoming these pitfalls requires ongoing attention and learning about your specific plan’s details, as 401k rules and options vary by employer and plan provider.

What Are the Most Common 401k Mistakes and Their Costs?

Here are the six most frequent mistakes people make with 401k plans, what they cost you, and how to avoid them:

1. Not Contributing Enough to Get the Full Employer Match Cost: Missing out on free money that can significantly boost your savings. For example, if your employer matches 50% up to 6% of your salary, not contributing at least 6% means losing that extra 3% addition. What to Do Instead: Always contribute at least enough to get the full employer match. Treat it like an instant 50% return on your contributions.

1. Cashing Out Early or Taking Loans Without a Plan Cost: Early withdrawals often come with taxes and penalties, plus lost compounding growth. For example, withdrawing $10,000 early might incur a 10% penalty plus income taxes, reducing the amount you keep and future earnings. What to Do Instead: Avoid withdrawals unless absolutely necessary. If you need funds, consider options like hardship withdrawals or loans carefully, understanding repayment terms.

1. Failing to Diversify Investments Cost: Concentrating your portfolio in one type of investment can increase risk and reduce growth potential. For example, putting all your money in company stock risks a big loss if the company falters. What to Do Instead: Diversify across stocks, bonds, and other assets based on your age and risk tolerance. Most plans offer target-date funds which automatically adjust investments over time.

1. Ignoring Fees and Expenses Cost: High fees can erode your returns over time. For example, paying 1% annual fees on a $100,000 balance costs $1,000 a year, which adds up significantly over decades. What to Do Instead: Review your plan’s fee disclosures, choose low-cost funds, and ask your plan administrator about any hidden fees.

1. Not Updating Beneficiaries Cost: If your beneficiary designations are outdated, your money might go to someone you no longer want to inherit it, causing family disputes or legal issues. What to Do Instead: Review and update beneficiary information regularly, especially after life changes like marriage, divorce, or having children.

1. Making Rollover Mistakes When Changing Jobs Cost: Cashing out a 401k during a job change instead of rolling it over can trigger taxes and penalties and disrupt long-term growth. What to Do Instead: Roll over your 401k directly into your new employer’s plan or an IRA to keep your savings tax-advantaged and growing.

How Can You Recover If You Already Made a 401k Mistake?

If you’ve made mistakes like cashing out early or not contributing enough, it’s never too late to improve your strategy. Here are practical steps to recover:

• Restart Contributions: Begin contributing as much as your budget allows, aiming to catch up over time.
• Use Catch-Up Contributions: If you are 50 or older, take advantage of catch-up contribution limits your plan offers.
• Review Investment Choices: Rebalance your portfolio to align with your retirement goals and risk tolerance.
• Consider a Rollover: If you left a job and cashed out, consider rolling any remaining funds from old accounts into one place to simplify management.
• Consult a Financial Advisor: For complex situations, professional advice can help you plan a recovery strategy tailored to your needs.

What Habits Prevent 401k Mistakes?

Building consistent habits can help avoid common 401k errors:

• Automate Contributions: Set your payroll to automatically contribute at least enough to get the employer match.
• Schedule Annual Reviews: Check your beneficiary designations, fees, and investment mix once a year.
• Stay Informed: Keep up with plan changes and IRS rules about contributions and withdrawals.
• Avoid Emotional Decisions: Resist the urge to withdraw early, especially during financial stress, and seek alternatives first.
• Use Available Tools: Many plans offer online calculators or guidance tools to help you understand your savings progress and options.

What Are Specific Mistakes That Boomers Often Make with 401ks?

Boomers face unique challenges that can lead to costly mistakes such as:

• Delaying Required Minimum Distributions (RMDs): Failing to take RMDs from traditional 401ks after age 73 can incur heavy IRS penalties.
• Ignoring Roth Conversion Opportunities: Converting some funds to a Roth 401k or IRA while still working can reduce future tax burdens.
• Withdrawing Too Quickly After Retirement: Rapid withdrawals can deplete savings faster than planned.
• Not Coordinating Social Security with 401k Withdrawals: Poor timing can increase tax burdens or reduce benefits.

Boomers should work with financial planners to create withdrawal strategies that optimize taxes and income longevity.

How Can You Avoid 401k Withdrawal Mistakes?

401k withdrawal mistakes often result in unnecessary taxes and penalties. To avoid them:

• Understand Withdrawal Rules: Withdraw from traditional 401ks after age 59½ to avoid the 10% penalty unless exceptions apply.
• Plan for Taxes: Withdrawals are taxed as ordinary income, so plan withdrawals to minimize tax impact.
• Take Required Minimum Distributions on Time: Starting at age 73, IRS rules require minimum withdrawals to avoid penalties.
• Avoid Early Cash-Outs: If you must access funds early, check if hardship withdrawals apply and understand tax consequences.

Planning withdrawals strategically supports a more secure retirement budget.

What Are Common 401k Rollover Mistakes and How Can You Avoid Them?

When changing jobs or retiring, mistakes in rolling over your 401k can cost taxes and penalties:

• Withdrawing Instead of Rolling Over: Taking cash out rather than transferring funds leads to taxes and penalties.
• Missing the 60-Day Rollover Deadline: Indirect rollovers must be completed within 60 days to avoid taxes.
• Not Rolling Over to an IRA or New Employer’s Plan: Leaving money in an old plan can cause confusion and higher fees.
• Ignoring Beneficiary Designations on New Accounts: Failing to update beneficiaries after rollover can cause estate issues.

To avoid rollover mistakes, opt for direct rollovers between accounts and confirm all paperwork is completed promptly.

Frequently asked questions

Can I contribute to my 401k and an IRA at the same time?

Yes, you can contribute to both as long as you meet IRS income limits and contribution rules. This approach can help diversify your retirement savings and provide different tax advantages.

What happens if I don’t update my 401k beneficiary after a life change?

If beneficiary information is outdated, your 401k funds could go to someone you didn’t intend, potentially causing legal challenges and family conflict.

How much should I contribute to my 401k each year?

Aim to contribute at least enough to get the full employer match, then increase your contributions over time. The IRS sets annual contribution limits, which you can check each year.

What is the penalty for withdrawing from a 401k before age 59½?

Generally, early withdrawals incur a 10% penalty plus income taxes on the amount withdrawn, unless you qualify for certain exceptions.

Can I roll over my 401k to a Roth IRA?

Yes, but converting a traditional 401k to a Roth IRA triggers income tax on the converted amount. This move can be beneficial long term but should be planned carefully.

How do I avoid high fees in my 401k plan?

Review your plan’s fee disclosures, choose low-cost index or target-date funds, and ask your plan administrator about any fees that seem unclear or excessive.