How to use the 401(k) Calculator
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How this 401k calculator works
Each year, the calculator adds your contributions and your employer match to the balance, then grows the total at the return you enter. Your contributions rise with your salary growth, so a raise also raises what you save. The result splits into what you put in, what your employer added and what investment growth produced, which shows how much of a 401(k) balance comes from time in the market.
Matching contributions and taxes
Matching contributions are the easiest win in retirement savings. If your plan matches 50% of what you put in up to 6% of pay, contributing less than 6% leaves part of your pay on the table. With a traditional 401(k), money goes in before income tax and grows tax deferred. With a Roth 401(k), you pay tax now and qualified withdrawals come out tax free. Many people also use an individual retirement account (IRA) alongside their workplace plan.
Choosing an expected return
401(k) investments are usually mutual funds or target date funds, and their returns change every year. A long-term average of 5 to 7% a year before inflation is a common planning range for a mix of stocks and bonds, but it is not a promise. Try a lower rate as well to see a more cautious picture of your retirement account.
The formula
Yearly: balance = (balance + contributions) × (1 + return), contributions rise with salary.
Examples
- $80,000 salary, 8% contribution, 50% match up to 6%, 30 years
Projected balance after 30 years: $1,116,813.06 Your contributions: $304,482.66 Employer match: $114,181.00 Investment growth: $678,149.40
- Same plan contributing 10%
Projected balance after 30 years: $1,298,984.55 Your contributions: $380,603.33 Employer match: $114,181.00 Investment growth: $784,200.23
- Starting later: 20 years at 8% contribution
Projected balance after 20 years: $487,438.83 Your contributions: $171,970.40 Employer match: $64,488.90 Investment growth: $230,979.54
Limitations and assumptions
The 2026 IRS employee deferral limit is $24,500 (check irs.gov for your age and plan). Projection only.
Frequently asked questions
How does an employer match work?
Your employer adds a percentage of what you contribute up to a cap. A 50% match up to 6% of pay means 3% of your salary from the employer if you contribute at least 6%.
How much should I contribute?
At minimum enough to get the full match. Many planners suggest 10 to 15 percent of income including the match.
What return should I assume?
The result is only as good as the assumption. Use a conservative figure and test a lower one too.
Are contribution limits applied?
This projection does not enforce IRS limits, so check the current annual contribution limit for your age.