What is a 401(k) Calculator?

A 401(k) calculator is a retirement planning tool that estimates how much money you’ll accumulate in your 401(k) account by the time you retire. By entering your current balance, salary, contribution rate, employer match, and expected investment return, it projects your retirement savings using compound growth over time.

A 401(k) is the most common employer-sponsored retirement savings plan in the United States. Contributions are made pre-tax (traditional 401(k)) or post-tax (Roth 401(k)), and investments grow tax-deferred until withdrawal in retirement. Understanding your projected balance helps you determine whether you’re on track — or need to increase contributions now.

How is a 401(k) Balance Calculated?

Your 401(k) grows through four sources: your opening balance compounding over time, your own contributions, your employer’s matching contributions, and investment earnings on all of the above.

Example: Starting with $25,000 at age 35, earning $75,000 p.a., contributing 6% with a 50% employer match up to 6%, at 7% annual returns — you’d project approximately $820,000 by age 65.

How to Use This 401(k) Calculator

Enter your current 401(k) balance — find this in your plan portal or most recent statement. Enter your annual pre-tax salary. Set your contribution rate — the percentage of your salary you contribute each paycheck. Enter your employer match rate and match cap — for example, “50% match up to 6% of salary” means match rate = 50%, cap = 6%. Enter your current age and target retirement age (59½ is the earliest penalty-free withdrawal age). Set your expected annual investment return. Toggle inflation adjustment to see your result in today’s purchasing power.

What Your 401(k) Result Means

The projected balance is your estimated 401(k) value at retirement. The monthly income estimate assumes you draw down your balance evenly over 20 years — a simplified model that doesn’t account for Social Security income, which most American retirees also receive.

One of the most powerful insights the calculator reveals is the value of the employer match. A 50% match up to 6% is effectively a 3% instant salary boost — never leave that on the table.

Is This Calculator Accurate?

This 401(k) calculator is a planning tool and provides estimates, not guarantees. It does not model taxes on traditional 401(k) withdrawals (typically taxed as ordinary income in retirement), Required Minimum Distributions (RMDs) which begin at age 73, the impact of market volatility year to year, salary increases over time, or changes to IRS contribution limits. For a comprehensive retirement projection, use your plan provider’s tools or speak with a Certified Financial Planner (CFP).

How to Choose Your Inputs

Contribution rate: The IRS 2025 limit is $23,500 for those under 50, and $31,000 for those 50 and older (catch-up contributions). As a percentage, most financial advisers recommend contributing at least enough to capture the full employer match as a starting point, then working toward 15% total (including match). Employer match: Check your Summary Plan Description (SPD) or HR documents. Common structures are “100% of the first 3%” or “50% of the first 6%.” Investment return: The S&P 500 has averaged ~10% annually before inflation over 90+ years. A diversified target-date fund typically projects 6–8% depending on your time horizon.

Suitable for Women

Yes — this 401(k) calculator applies equally to all workers. However, women face a retirement savings gap similar to the broader pay gap: lower average salaries and career breaks for caregiving can result in smaller 401(k) balances over time. Women also tend to live longer in retirement, making a larger accumulated balance more important. Maximising contributions during peak earning years and ensuring continued contributions during any part-time periods can significantly close this gap.

Suitable for Men

Yes — this calculator works for any US employee with a 401(k). Men statistically contribute slightly more to retirement accounts on average, but also tend to take on more investment risk. The calculator’s return rate input lets you model both conservative and aggressive portfolio assumptions. Men with higher salaries should pay particular attention to the IRS annual contribution limit, which caps the tax advantage of 401(k) contributions regardless of salary.

Can I Use This for Roth 401(k) Planning?

Yes, with one important caveat. The growth projection is the same for both traditional and Roth 401(k) plans — your money compounds identically either way. The key difference is tax treatment: traditional 401(k) contributions are pre-tax (you pay tax on withdrawal), while Roth 401(k) contributions are post-tax (withdrawals in retirement are tax-free). If you expect to be in a higher tax bracket in retirement, a Roth 401(k) may be more beneficial. The projected balance shown here represents your gross balance before any withdrawal taxes on a traditional 401(k).

401(k) vs Other Retirement Accounts

The 401(k) is one of several US retirement accounts. An IRA (Individual Retirement Account) has a lower 2025 contribution limit of $7,000 ($8,000 if 50+) but is available to anyone with earned income. A Roth IRA offers tax-free growth with income limits for eligibility. A 403(b) is similar to a 401(k) but for non-profit, school, and government employees. For most employees with access to an employer match, maximising the 401(k) match first, then maxing an IRA, then returning to the 401(k) is the standard recommended order of operations.

Key 401(k) Rules & Limits (2025)

• Employee contribution limit (under 50): $23,500
• Catch-up contribution (age 50–59 and 64+): Additional $7,500
• Super catch-up (age 60–63): Additional $11,250 (new for 2025)
• Total combined limit (employee + employer): $70,000
• Penalty-free withdrawal age: 59½
• Required Minimum Distributions begin: Age 73
• Early withdrawal penalty: 10% plus ordinary income tax

For the most current contribution limits and rules, visit the IRS 401(k) contribution limits page.

Frequently Asked Questions