401(k) Calculator – Contributions, Growth & Match

A 401(k) is one of the most powerful tools you have for retirement. Your contributions, your employer match and decades of compounding can turn a modest saving rate into a six- or even seven-figure balance. This 401(k) calculator helps you see how your balance could grow over time, how much of that growth comes from employer matching contributions and whether you are getting close to current IRS limits.

How this 401(k) calculator models contributions, match and growth

The HonestCredit 401(k) calculator focuses on three big drivers of your retirement savings: how much you earn, how much you and your employer contribute and how long those contributions have to grow. Behind the scenes it simulates each year between now and retirement, applies your contribution and match settings and then compounds the balance at the annual return you choose.

On the contribution side, the tool uses:

• Annual salary today as the starting point for your contributions.
• Your contribution rate as a percentage of pay, such as 6 percent, 10 percent or 15 percent.
• Employer match rate, for example a 50 percent match, and a match cap, such as up to 4 percent or 6 percent of your salary.
• Current 401(k) balance as the starting value that can also grow over time.
• Annual salary growth so your contributions can increase as your pay increases.

On the growth side, the calculator:

• Applies an expected annual investment return to your balance after contributions and match each year.
• Separately tracks the dollars that come from your contributions, employer contributions and investment growth.
• Uses current IRS employee contribution limits as guardrails so extremely high contribution rates do not push the numbers far beyond what is allowed under the rules.

For example, the IRS employee contribution limit (elective deferrals) is $23,500 for 2025 and is scheduled to rise to $24,500 for 2026, with additional “catch-up” room for savers age 50 and older. Employer matching contributions do not count toward that employee deferral limit, but they do count toward a higher overall cap on total annual contributions from all sources. The tool captures the most important constraint for most savers by capping the employee portion while still allowing employer contributions to be added on top.

To help you think in terms of retirement income, the calculator also estimates how much annual and monthly income a 4 percent withdrawal from this 401(k) alone could provide in retirement and compares that amount with your projected future salary. That makes it easier to see whether this account is likely to replace a small share of your income, something closer to half or potentially even more.

Reading your 401(k) results: balance, income and match usage

The results panel is designed to show not just the final number, but also what is driving it and how that ties back to your real life. Understanding each line helps you translate the math into a concrete savings plan.

The first card focuses on your estimated 401(k) balance at retirement. This is the projected account value based on your inputs. Under that you will see:

• Your contributions (total): the sum of all dollars you are expected to contribute between now and retirement.
• Employer match (total): the value of matching contributions your employer may add on top of your own savings.
• Investment growth: the portion of the ending balance that comes from compounding rather than fresh contributions.

The horizontal bar beneath those numbers highlights how important compounding can be. Over several decades it is common to see investment growth dwarf the dollars you contribute, even if your starting balance is modest. At the same time, the employer match slice shows how valuable it is to contribute at least enough to unlock the full match if you can.

The second card focuses on income potential:

• Annual income from this 401(k) (4% rule): a rough estimate of how much you could withdraw each year while trying to preserve the portfolio over a long retirement.
• Monthly income from this 401(k): the same number expressed on a monthly basis for easier comparison with your budget.
• Share of projected salary replaced: this compares the 4 percent withdrawal with your projected salary at retirement, based on the salary growth rate you entered.

The third card looks at saving rate and match usage:

• Total saving rate from your pay: your own contribution rate plus the approximate percent of salary your employer is adding through the match.
• Use of IRS employee limit: an estimate of how much of the current 401(k) employee contribution limit you are using with your chosen savings rate.
• Match status: a simple label that indicates whether you are contributing enough to earn the full match based on the match settings you entered.

If the status shows that you are not yet getting the full match, even a small increase in your contribution rate can have a large impact: you are adding more of your own money and unlocking more employer contributions at the same time. If you are already using most of the available employee limit, additional increases may be limited and you might focus on other accounts, such as an IRA or health savings account, subject to their own rules.

How much of your income should go into a 401(k)?

There is no single contribution rate that is right for everyone, but there are some useful benchmarks. Many large retirement providers suggest targeting roughly 15 percent of your gross income for retirement savings over your career, including any employer match. For example, if your employer matches 4 percent of your pay, you might contribute around 11 percent yourself to get close to that combined target. This is a guideline, not a hard rule, and the right number for you depends on when you start saving, how much you have already accumulated, how aggressively you invest and when you hope to retire.

At a minimum, many experts encourage savers to contribute enough to receive the full employer match if one is offered. That match is effectively part of your compensation package. Passing it up usually means giving up a very high, risk-free return on those dollars. If your budget is tight, you can start by contributing just enough to capture the full match and then work toward higher contribution rates over time.

If you are starting later or feel behind, the calculator can help you see how higher contribution rates, an extended working life or a combination of both might help you close the gap. You can also experiment with different investment return assumptions to understand whether you are relying on aggressive growth to make the numbers work or whether your plan looks realistic even with more modest returns.

Step by step: how to use the 401(k) calculator with your own numbers

You do not need to be an expert to get value from this tool. Here is a simple way to use the calculator and interpret the results.

1. Enter your age and planned retirement age. Make sure there are at least several years between the two; the calculator will flag unrealistic combinations. If you are not sure about the exact year, use your best estimate and test a range.
2. Add your current salary and 401(k) balance. Use your gross annual pay before taxes and the current balance in this 401(k), not including separate IRAs or other accounts.
3. Set your contribution rate and employer match. Enter the percent of salary you contribute and then the match formula from your plan description, such as 50 percent up to 6 percent of pay.
4. Choose investment return and salary growth assumptions. For a diversified long-term portfolio, many people test real-world return assumptions in the mid- to high-single digits and then add a conservative case and a more optimistic case.
5. Review the projected balance and breakdown. Look at how much of the final number comes from your contributions, employer contributions and growth. This can be motivating and can highlight the value of matches.
6. Check your income replacement and IRS limit usage. Ask whether the 4 percent withdrawal and share of income replaced feel comfortable relative to your goals. Also review how much of the current employee contribution limit you are using.
7. Experiment with changes. Increase or decrease your contribution rate, adjust your planned retirement age or change salary growth and investment return assumptions one input at a time to see how sensitive the results are.

IRS 401(k) limits, catch-up rules and plan details to keep in mind

The IRS updates 401(k) contribution limits periodically to reflect inflation. For 2025, the employee contribution limit for most workers is $23,500, with an additional catch-up allowance for those age 50 and older. For 2026, the employee limit rises to $24,500, and workers age 50 or older can contribute more through catch-up contributions. On top of this, there is a higher cap on total contributions from all sources combined, including employer match and any profit-sharing contributions. Most workers never reach that total cap, but high earners and those with generous matches sometimes get close.

The calculator incorporates these rules in a simplified way by capping annual employee contributions at the current employee limit and allowing employer contributions on top. It does not model all of the detailed scenarios, such as special additional catch-up room in certain years or every nuance of the total contribution cap. If you are close to the limits, it is important to confirm the exact rules that apply to your plan and tax year using official IRS guidance or a tax professional.

Remember that 401(k) plans can also include vesting schedules for employer contributions. You always own the money you contribute yourself, but some or all of your employer match may be forfeited if you leave the company before you are fully vested. The calculator assumes all employer contributions ultimately remain in your account for simplicity.

Making your 401(k) part of a broader retirement plan

A 401(k) is often the central pillar of a retirement strategy, but it is rarely the only piece. Social Security benefits, other employer plans, IRAs, taxable investment accounts and even home equity can all play a role in funding your retirement. The calculator on this page looks specifically at one 401(k) account so that you can understand its contribution to your overall plan.

Once you are comfortable with your 401(k) trajectory, it can help to:

• Review your investment mix and make sure it lines up with your risk tolerance and time to retirement.
• Check your beneficiaries and keep them up to date after major life events.
• Consider whether Roth contributions, if available in your plan, might help diversify your future tax exposure.
• Coordinate 401(k) savings with IRAs or other accounts so that you are not overlooking additional tax-advantaged opportunities.

As you get closer to retirement, you may want to use this 401(k) calculator together with a broader retirement planning or income tool that incorporates all of your accounts, expected Social Security benefits and spending goals. That way, you can move from the question of “How big could this account get?” to “How do I turn my savings into a sustainable and flexible income plan?”