A 401(k) grows from three sources: the money you defer from each paycheck, the money your employer adds, and decades of investment growth on both. This 401(k) calculator projects all three year by year. It raises your pay over time, applies your plan’s match formula, and caps contributions at the 2026 IRS limits, including the age-based catch-ups. The result is your balance at retirement, in future dollars and in today’s dollars.
How to use the 401(k) calculator
- Enter your current age, the age you plan to retire and your current 401(k) balance.
- Enter your annual salary and the raise you expect each year.
- Enter the percentage of pay you contribute and your plan’s match: the match rate (50% means 50 cents per dollar) and the share of pay it applies to.
- Keep IRS limits checked so contributions stop at the legal maximum, with catch-ups added from the year you turn 50.
- Set the annual return, your plan’s fees and an inflation rate for today’s-dollar values.
How the projection works
Each year the calculator works out your contribution and the employer’s:
One-twelfth of the year’s total goes in at the end of every month. The balance earns a monthly return of (1 + annual return)1/12 − 1 and pays one-twelfth of the yearly fee each month. Salary rises once a year by your raise. The IRS limits start at their 2026 amounts and rise with the inflation rate you enter, roughly how the IRS indexes them in $500 steps.
2026 contribution limits
The IRS announced these limits in Notice 2025-67:
| Limit | 2026 amount |
|---|---|
| Employee elective deferral | $24,500 |
| Catch-up, age 50 and older | $8,000 (total $32,500) |
| Catch-up, ages 60 to 63 | $11,250 (total $35,750) |
| Employee + employer (Section 415(c)) | $72,000 |
| Pay counted toward employer contributions | $360,000 |
Catch-up eligibility depends on the age you reach by December 31, so the calculator uses the age you turn in each projection year. The higher 60-to-63 catch-up comes from the SECURE 2.0 Act and drops back to the regular catch-up the year you turn 64.
Worked example
You are 35 with $40,000 saved and earn $80,000, with 3% raises. You contribute 8%, and your employer matches 50% of contributions up to 6% of pay. You assume a 7% return, 0.25% in fees and 2.5% inflation, and plan to retire at 65.
- Year one: you put in $6,400 and your employer adds $2,400 (50% of 6% of $80,000).
- Balance at 65: $1,408,475.17, or about $671,480 in today’s dollars.
- Of that, $304,482.66 came from you, $114,181.00 from your employer and $949,811.51 from growth.
How the contribution rate changes the outcome
Same saver, same assumptions:
| You contribute | Balance at 65 | Employer match collected |
|---|---|---|
| 3% | $743,118 | $57,091 |
| 6% | $1,203,750 | $114,181 |
| 8% | $1,408,475 | $114,181 |
| 10% | $1,613,200 | $114,181 |
| 15% | $2,125,013 | $114,181 |
Going from 3% to 6% adds about $460,000, in part because it doubles the match. Past 6% the match is maxed out and each extra point adds roughly $100,000 here.
Making the most of a 401(k)
Contribute at least enough to get the full match. It is an immediate return on your money that no investment reliably beats. After that, compare the 401(k) with an IRA: the Roth IRA calculator checks your 2026 eligibility, and the Roth vs. traditional calculator shows whether pre-tax or Roth contributions leave you with more. Keep an eye on fees, and check your plan’s vesting schedule. Employer money may not be fully yours until you have worked there a set number of years.
When you retire, the balance has to last. The retirement withdrawal calculator shows how long it lasts at a given spending rate. Once you reach your required beginning age, the RMD calculator works out the minimum the IRS requires you to withdraw each year.
Estimates only, not financial, tax or investment advice. Returns are not guaranteed, and your plan's rules (match formula, vesting, Roth options) control the actual figures.
Frequently asked questions
What is the 401(k) contribution limit for 2026?
The IRS set the 2026 employee deferral limit at $24,500. Workers age 50 or older can add an $8,000 catch-up, and those who turn 60, 61, 62 or 63 during the year can add $11,250 instead. Employee plus employer contributions together are capped at $72,000, not counting catch-ups.
How does an employer match work?
A common formula is 50% of what you contribute, on contributions up to 6% of pay. On an $80,000 salary you would need to put in $4,800 (6%) to receive the full $2,400 match. Contributing less leaves part of the match unclaimed, and the calculator shows how much.
Do I have to make catch-up contributions as Roth?
Starting in 2026, yes, if your FICA wages from the same employer exceeded $150,000 in the prior year. Those catch-up dollars must go in as Roth (after-tax) contributions. Your regular deferrals can still be pre-tax.
What return should I assume?
Many planners use 5% to 7% a year for a stock-heavy portfolio over long periods, and less as you shift toward bonds. Because the result is very sensitive to this number, try a lower rate as well to see a cautious case.
Why do fees matter so much?
Fees come out of the balance every year, so they compound just like returns do. In the default example, raising total fees from 0.25% to 1% cuts the projected balance at 65 from about $1.41 million to about $1.21 million.