401(k) Calculator

Employer Matching: The Only Guaranteed 100% Return in Finance

If your employer offers a 401(k) match and you are not contributing enough to capture it fully, you are declining free money. Not metaphorically, not as a figure of speech. Literally declining cash that your employer is willing to deposit into your retirement account in exchange for nothing more than your participation.

Here is how it works in practice. Say you earn $80,000 per year and your employer matches 50% of your contributions up to 6% of your salary. If you contribute 6% of your pay ($4,800 per year), your employer deposits an additional $2,400 into your account. That $2,400 costs you nothing. It is a 50% instant return on your $4,800 contribution before the market even opens, before a single share of anything is purchased.

Now consider what happens when you contribute less. At 3% contribution ($2,400/year), your employer only matches 50% of that, giving you $1,200 instead of $2,400. You are leaving $1,200 per year on the table. Over a 30-year career with 8% average annual investment returns, that $1,200 annual shortfall compounds into approximately $136,000 in lost wealth. Double that for the full $2,400 annual gap if you contribute nothing at all, and you are looking at $272,000 that simply evaporated because you did not fill out a form.

Some employers offer even more generous structures: dollar-for-dollar matching up to 4%, or 50% match up to 8%. The specifics vary, but the principle does not. The absolute minimum contribution for any 401(k) participant should be whatever percentage captures the full employer match. Anything below that threshold represents a guaranteed, quantifiable loss. There is no investment in the world that offers a risk-free 50% or 100% return. Your employer match is the closest thing that exists. To see how your matched contributions grow through compound interest over decades, run the numbers in our dedicated calculator.

Traditional vs. Roth 401(k): A Tax Bracket Decision

The traditional-versus-Roth debate is not a philosophical or ideological question. It is a math problem, and the answer depends on one specific variable: will your marginal tax rate be higher or lower in retirement than it is right now?

Scenario 1: You expect lower taxes in retirement. If you are currently in the 22% federal bracket (single filers earning $44,726 to $95,375 in 2024) and expect your retirement income to place you in the 12% bracket, traditional contributions win. Every dollar you contribute today saves you 22 cents in taxes. When you withdraw that dollar in retirement, you only pay 12 cents. On a $23,000 annual contribution, that is $5,060 in tax savings now versus $2,760 in taxes later, netting you $2,300 per year in pure tax arbitrage. Over 30 years with investment growth, that tax savings compounds into a meaningful difference in your total retirement wealth.

Scenario 2: You expect higher taxes in retirement. If you are early in your career earning $45,000 (sitting in the 12% bracket) and expect your income and tax bracket to climb over the coming decades, Roth is the better play. You pay 12% on contributions now, and every single dollar of growth comes out completely tax-free in retirement. Consider the magnitude of this: a $23,000 Roth contribution growing at 8% for 35 years becomes roughly $344,000, and you owe zero taxes on any of it. In a traditional account at a 22% withdrawal rate, that same $344,000 would cost you about $75,700 in taxes at distribution.

Scenario 3: You genuinely have no idea. Many financial advisors recommend splitting contributions between traditional and Roth when the future is uncertain. This creates tax diversification in retirement, giving you two separate pools to draw from. In years when you have higher taxable income (maybe you sold a property or took a large required minimum distribution), you can pull from the Roth bucket to avoid pushing yourself into a higher bracket. In lower-income years, you draw from the traditional account and pay taxes at a reduced rate. Having both options available is itself a form of financial flexibility that has real value.

2024 Contribution Limits and Catch-Up Rules

The IRS adjusts 401(k) contribution limits annually for inflation, and understanding these ceilings is essential for maximizing your tax-advantaged savings. For 2024, the numbers are:

• Employee contribution limit (under 50): $23,000
• Catch-up contribution (age 50+): additional $7,500, bringing the total to $30,500
• Total combined limit (employee + employer): $69,000 under 50, $76,500 with catch-up

The catch-up provision exists specifically because many people in their 50s are in their peak earning years and are trying to make up for earlier decades when they could not save as much. That extra $7,500 per year for 15 years at 8% returns adds approximately $204,000 to your retirement balance. If you are over 50 and not using catch-up contributions, you are leaving a significant planning tool on the shelf.

The combined $69,000 limit matters for one powerful and often overlooked reason: the mega backdoor Roth. If your employer plan allows after-tax (non-Roth) contributions beyond the $23,000 pre-tax/Roth limit, you can contribute up to the $69,000 combined ceiling and then convert those after-tax dollars to Roth. This creates a legal pathway for high earners to shelter significantly more money in tax-free Roth accounts each year. Not every employer plan supports this structure, so check your Summary Plan Description or ask your HR department. If yours does, it is one of the most powerful wealth-building tools available.

What does maxing out look like long term? Contributing $23,000 per year for 30 years at an 8% average return yields approximately $2.6 million. If you add catch-up contributions of $30,500 per year for the final 15 years instead of $23,000, you end up closer to $3.0 million. These are projections, not guarantees, but they illustrate why the IRS caps these contributions: the tax advantages are extraordinarily valuable over a full career.

The True Cost of a 401(k) Loan

On the surface, borrowing from your 401(k) sounds perfectly reasonable. You are borrowing from yourself, paying interest to yourself, and avoiding a bank's underwriting process and fees. In practice, a 401(k) loan is one of the most expensive financial moves you can make, and the true cost is almost always invisible until it is too late.

Here is what actually happens when you take a $20,000 loan from your 401(k):

Problem 1: You repay with after-tax dollars. Your original 401(k) contributions were pre-tax, meaning they went in before the IRS took its cut. But loan repayments come from your net paycheck, meaning you have already paid income tax on that money. When you eventually withdraw those repaid dollars in retirement, you get taxed on them again as ordinary income. That is double taxation on every single repayment dollar. On a $20,000 loan repaid by someone in the 22% bracket, that double taxation costs roughly $4,400 in extra lifetime taxes.

Problem 2: You miss market gains during the loan period. The $20,000 you borrowed is pulled out of your investments. It is no longer in the market working for you. If you take two years to repay the loan and the market returns 8% annually during that period, you miss out on roughly $3,300 in direct growth. But the cost does not stop there. That $3,300 you missed also loses the chance to compound for the remaining 25 years until retirement. At 8%, that missed growth balloons to approximately $23,000 in lost future wealth. You cannot see this cost on any statement, but it is real.

Problem 3: Job loss triggers a full and immediate repayment. If you leave your employer while a 401(k) loan is outstanding, whether you quit, get laid off, or are terminated, most plans require full repayment within 60 to 90 days. If you cannot repay within that window, the outstanding balance is reclassified as a taxable distribution. You owe income tax on the full amount plus a 10% early withdrawal penalty if you are under 59 and a half. On a $20,000 balance for someone in the 22% bracket, that means roughly $6,400 in taxes plus a $2,000 penalty, totaling $8,400 in immediate costs, on top of losing the retirement savings entirely.

Add it all up: a $20,000 401(k) loan that you repay over two years can realistically cost you $43,000 or more by retirement when you account for lost compounding, double taxation, and the risk of forced distribution. Before borrowing from your future retirement, exhaust every other option. An emergency fund, a home equity line of credit, even a personal loan at a reasonable interest rate will almost always be cheaper than raiding your 401(k). Your future self is the one who pays the real price, and they will not have the option to go back and undo it.