How it works
Understanding the inputs
- Contribution % — the share of each paycheck you defer into the plan. The calculator caps it at the IRS elective-deferral limit for your age.
- Employer match — many employers match a percentage of what you put in, up to a percentage of salary. “100% up to 5%” means that if you contribute at least 5% of pay, your employer adds another 5%. “50% up to 6%” means they add 3% when you contribute 6%.
- Salary increase — your expected average annual raise. Because contributions are a percentage of pay, raises increase both your deferrals and the match.
- Expected return — an assumed average annual return after fund fees. Real returns vary year to year and can be negative.
2026 contribution limits used
- Employee elective deferrals: $24,500.00
- Catch-up for age 50+: $8,000.00 (total $32,500.00)
- Higher catch-up for ages 60–63 (SECURE 2.0): $11,250.00 (total $35,750.00)
- Total employee + employer additions (Section 415(c)), excluding catch-up: $72,000.00
Limits are held at 2026 levels for every future year. The IRS normally raises them for inflation, so this is a conservative assumption for high savers.
The formula
Each year the calculator works out your contribution, E = min(salary × contribution %, limit for your age), and the employer match, M = match % × min(E, salary × match limit %). One-twelfth of E + M is added at the end of each month, and the balance grows monthly at the expected return ÷ 12:
balancemonth = balance × (1 + r/12) + (E + M) / 12
Salary then increases by your raise percentage for the next year.
Worked examples
Age 30, $70,000 salary, 3% raises, 10% contribution, 100% match up to 5%, $20,000 balance, 7% return, retire at 65
Year-1 contributions: $7,000.00 from you plus $3,500.00 employer match. Projected balance at 65: $2,458,894.97 — $423,234.57 contributed by you, $211,617.29 from your employer and $1,804,043.11 of investment growth.
Age 45, $150,000 salary, 2% raises, 20% contribution, 50% match up to 6%, $250,000 balance, 6% return, retire at 67
20% of pay ($30,000.00) exceeds the $24,500.00 limit, so year-1 deferrals are capped at $24,500.00; catch-up contributions apply from age 50 and the higher catch-up at 60–63. Projected balance at 67: $2,543,544.62 (you: $688,000.00, employer: $122,845.43).
How much should you contribute?
Always capture the full match. An employer match is an instant return on your money. In the first example, contributing 10% instead of 3% (which forfeits part of a 100%-up-to-5% match) grows the projected balance from $1,121,631.81 to $2,458,894.97. Even contributing exactly 5% gets the full match and projects to $1,715,970.99.
Increase gradually. If 15% feels out of reach, raise your rate by 1 percentage point each year or each time you get a raise. Many plans offer automatic escalation.
Use catch-up contributions. From the year you turn 50 you can add $8,000.00 more, and in the years you turn 60 through 63 the extra amount rises to $11,250.00. Starting in 2026, if your prior-year wages from the employer exceeded $150,000, catch-up contributions must be made as Roth contributions.
What affects your 401(k) balance
- Time. Compounding does most of the work over long periods — starting five years earlier can matter more than contributing a few extra percent later.
- Fees. A fund charging 1% a year instead of 0.1% can cost tens of thousands of dollars over a career. Enter your return net of fees.
- Vesting. Employer contributions may vest over several years; if you leave early you may forfeit some of the match. This calculator assumes you are fully vested.
- Traditional vs. Roth 401(k). Traditional contributions reduce taxable income now and are taxed at withdrawal; Roth contributions are taxed now and qualified withdrawals are tax-free. The balance shown is before any taxes on withdrawal.
- Inflation. A future balance buys less than the same amount today. Use the inflation calculator to convert it into today's dollars.
Frequently asked questions
What is the 401(k) contribution limit for 2026?
The 2026 employee elective-deferral limit is $24,500.00, up from $23,500 in 2025 (IRS IR-2025-111).
How much is the 401(k) catch-up contribution in 2026?
Employees age 50 and older can generally contribute an extra $8,000.00, for a total of $32,500.00. Under SECURE 2.0, employees who turn 60, 61, 62 or 63 during the year can contribute $11,250.00 instead, for $35,750.00.
Does the employer match count toward the $24,500 limit?
No. The $24,500.00 limit applies to your own deferrals. Employer contributions count toward the overall Section 415(c) limit of $72,000.00 for 2026 (not counting catch-up contributions).
How does an employer match work?
A match formula such as “100% up to 5% of salary” means your employer contributes $1 for every $1 you contribute, on contributions up to 5% of your pay. To get the full match you must contribute at least 5%.
What return should I assume?
Many planners use 5%–7% per year for a diversified stock-heavy portfolio over long periods, before inflation. Lower it for a more conservative portfolio or to be cautious. Returns are never guaranteed.
Are the limits adjusted in the projection?
No. To keep things simple and conservative, future years use the 2026 limits. In reality the IRS usually raises them for inflation.
Is the projected balance before or after taxes?
Before taxes. Withdrawals from a traditional 401(k) are taxed as ordinary income; qualified Roth 401(k) withdrawals are tax-free.