What is a 401(k) Calculator?
A 401(k) calculator estimates how your retirement account could grow from today until retirement based on your starting balance, contribution rate, employer match, salary growth, and expected market return. It is useful because retirement savings are not just about how much you put in. Compounding and employer contributions can change the final result a lot over time.
This calculator is built to show a realistic projection instead of a toy number. It separates your own contributions, your employer’s match, and investment growth so you can see where the final balance is actually coming from.
How This Calculator Works
The calculator converts your annual salary and contribution percentage into monthly contributions, then grows the balance month by month using your expected annual return. Salary growth is applied once per year, which keeps the projection closer to how real retirement planning works.
The chart shows two lines: your projected 401(k) balance and the balance you would have from contributions alone. That makes the compounding effect visible instead of hiding it.
Formula Logic
The projection uses recurring monthly compounding:
Balance grows monthly from existing assets + employee contributions + employer match
The employer match is capped by the percentage you enter, so the calculator can model common setups like “50% match up to 6% of salary.” Your actual plan may differ, so the assumptions are fully editable.
Why this matters
A 401(k) is one of the most important retirement tools for long-term investing because small changes in contribution rate, employer match, or expected return can produce a very large difference in the ending balance. This calculator helps you compare those choices clearly.
- See how much of your balance comes from your own money
- See how much comes from employer match
- See how much comes from compound growth
- Adjust assumptions before you make a retirement decision
How to use it
- Enter your current age and retirement age
- Add your current 401(k) balance
- Enter your annual salary
- Set your contribution rate, employer match, and salary growth
- Click calculate to see the projection and chart
Frequently Asked Questions
Yes. You can enter both the match percentage and the match limit. That lets the calculator estimate employer contributions alongside your own contributions.
Salary growth matters because your contributions usually grow as your income grows. Including it makes the projection more realistic over a long time horizon.
Yes. The line chart is the best format for this calculator because it shows the account path over time. One line shows the full projected balance, and the other shows contributions without investment growth.
No. It is a projection based on your assumptions. Real returns, salary changes, and plan rules can differ, so treat the result as a planning estimate.
Your projected balance rises because more money is invested each year, and employer matching may also increase depending on your plan settings.
Yes. It still shows how your own contributions and compounding can build a retirement balance over time, even without employer match.