401(k) calculator
Use the 401(k) calculator to project your retirement balance from your paycheck deferrals, your employer's match, and compound growth over time. Tweed's 401(k) calculator is different because it enforces the actual 2026 IRS contribution limits and SECURE 2.0 catch-up tiers automatically, so the number you see is one you could hand to a plan administrator.
Floored at 0% — a raise, never a pay cut, in this model
Compounded monthly
Projected balance at 65
$2,119,139
| Total you contributed | $475,754 |
| Total employer match | $142,726 |
| Total investment growth | $1,450,659 |
Models steady contributions and a constant rate of return, not what the market will actually do in any given year.
| Year | Age | Salary | Your deferral | Employer match | Balance |
|---|---|---|---|---|---|
| 1 | 35 | $100,000 | $10,000 | $3,000 | $66,912 |
| 5 | 39 | $112,551 | $11,255 | $3,377 | $151,699 |
| 10 | 44 | $130,477 | $13,048 | $3,914 | $307,328 |
| 15 | 49 | $151,259 | $15,126 | $4,538 | $540,668 |
| 20 | 54 | $175,351 | $17,535 | $5,261 | $885,400 |
| 25 | 59 | $203,279 | $20,328 | $6,098 | $1,389,145 |
| 30 | 64 | $235,657 | $23,566 | $7,070 | $2,119,139 |
Your numbers never leave your browser.
Verified July 24, 2026IRS Notice 2025-67, August 2026How we calculate this
Your monthly paycheck deferral is capped at the statutory elective-deferral limit for your age, your employer match is applied by your plan's tier structure, and the whole balance compounds monthly at your entered rate of return through your target retirement age.
In this article
How your 401(k) balance is calculated
Three things build your 401(k) balance: your paycheck deferrals, your employer's match, and compound growth. The calculator applies the 2026 IRS limits automatically, so you can't accidentally model a contribution rate you're not actually allowed to make.
Step 1: Your monthly paycheck deferral
Your contribution rate applies to your salary each pay period, and your salary itself grows with any annual raise you enter. Monthly deferral equals your contribution rate times that month's salary, divided across pay periods.
Step 2: 2026 IRS contribution limits, applied automatically
Elective deferrals are capped at $24,500 for anyone under 50 in 2026, $32,500 for ages 50–59 and 64+, and $35,750 for ages 60–63.1Combined employee-plus-employer additions can't exceed $72,000, or 100% of compensation, whichever is lower, under IRC §415(c).4The calculator caps your inputs at whichever limit applies to your age, rather than letting you enter an impossible number.
Step 3: Your employer match, calculated by tier
A single-tier formula matches a flat percentage up to a salary cap, like 50% on contributions up to 6% of salary. A dual-tier formula matches different rates across sequential thresholds, like 100% on the first 3% and 50% on the next 2%. Both are evaluated against the $360,000 annual compensation limit for 2026 under IRC §401(a)(17).4
Step 4: Monthly compounding through retirement
Deferrals and match are added each pay period and compound monthly at your entered rate of return through your target retirement age. This models steady contributions and a constant return, not what the market will actually do in any given year.
Understanding 401(k)s
What is a 401(k)?
A 401(k) is an employer-sponsored account for retirement savings, named for the tax code section that created it. Money comes out of your paycheck before it's taxed, or after tax if your plan offers a Roth option. Almost every employer that offers one adds some level of match on top;our upcoming guide on what a 401(k) is covers the account type in more depth.
How does a 401(k) grow tax-deferred?
Traditional 401(k) money and its growth stay untaxed until you actually withdraw it, so the full pre-tax amount keeps compounding every year instead of losing a slice to tax along the way. Roth 401(k)s work the other direction: you pay tax on contributions now, and qualified withdrawals later are free.
2026 401(k) limits, age milestones and tax rules
2026 contribution limits
All figures confirmed against IRS Notice 2025-67.1
| Parameter | 2026 | 2025 | Source |
|---|---|---|---|
| Elective deferral (§402(g)) | $24,500 | $23,500 | Notice 2025-67 |
| Standard catch-up, age 50+ | $8,000 | $7,500 | Notice 2025-67, §414(v)(2)(B)(i) |
| Super catch-up, ages 60–63 | $11,250 | $11,250 (unchanged) | Notice 2025-67, §414(v)(2)(E)(i) |
| Total defined contribution ceiling (§415(c)) | $72,000 | $70,000 | Notice 2025-67 |
| Annual compensation limit (§401(a)(17)) | $360,000 | $350,000 | Notice 2025-67 |
| High-earner Roth catch-up threshold | $150,000 | $145,000 | Notice 2025-67 |
Key age milestones in 401(k) planning
| Age | Rule | What it means |
|---|---|---|
| 50 | Standard catch-up eligibility | Add $8,000, for $32,500 total in 2026 |
| 55 | Rule of 55 | Penalty-free withdrawals from the plan of the employer you're separating from, if separation happens during or after the year you turn 555 |
| 59½ | Standard distribution age | Penalty-free withdrawals from any 401(k) |
| 60–63 | SECURE 2.0 super catch-up | $11,250 catch-up instead of $8,000, for $35,750 total, for exactly those four birth-year cohorts |
| 73 | RMD age, born 1951–1958 | Required minimum distributions begin |
| 75 | RMD age, born 1960 or later | Required minimum distributions begin |
Anyone born in 1959 sits between those two rows. The regulation covering that birth year is still pending, and a proposed rule would place it at 73,2but nobody born in 1959 reaches 73 until 2032, so there's no near-term decision riding on how it resolves. This page will update once it's settled.
Getting the most out of your employer match
An employer match is free money, but only up to your own contribution rate. Put in enough to get all of it, and dollar for dollar, it's usually the best return available anywhere, including the market itself.
How a typical tiered match works
Take a 50% match up to 6% of salary as an example. Contribute 6%, and your employer adds another 3%, so 9% of your salary goes into the account every pay period at no extra cost to you.
The front-loading risk, and why a "true-up" provision matters
Front-loading is the risk on the other side. Max out the $24,500 limit early in the year, which is common among higher earners, and your deferrals, and the match tied to them, can drop to zero for the rest of the year. Some plans fix this with a "true-up" provision that reconciles the shortfall in December; not all of them do, so it's worth asking your plan administrator before you front-load.
The SECURE 2.0 super catch-up, ages 60 to 63
That $11,250 figure only applies if you turn 60, 61, 62 or 63 sometime during the tax year, a number Notice 2025-67 confirms is unchanged for 2026.1Turn 64, and the catch-up drops back to the standard $8,000.
The high-earner mandatory Roth catch-up
If your prior-year FICA wages from the plan sponsor topped $150,000, every 2026 catch-up dollar has to go in as designated Roth.1You're trading after-tax money now for tax-free withdrawals down the road.
Worked example: 30 years of 401(k) growth
Consider an employee who is 35 today, plans to retire at 65, and already has $50,000 saved. Salary starts at $100,000 and grows 3% a year; the employee contributes 10%, the employer matches 50% up to 6% of salary, and the account earns 7% nominal a year, compounded monthly.
Year 1 ends with a balance of $66,912, built from $10,000 in employee contributions and $3,000 in employer match on top of the starting $50,000. By year 15, at age 50, salary has grown to $151,259; that year alone adds $15,126 from the employee and $4,538 from the match, and the account reaches $540,668.
By year 30, at age 65, salary reaches $235,657. Total employee contributions over the 30 years come to $475,754, total employer match reaches $142,726, and the account finishes at $2,119,139. Run your own salary, contribution rate and match formula through the calculator above to see your own number.
How we calculate your 401(k) balance
Every projection starts from the 2026 statutory limits in IRS Notice 2025-67, covering the elective-deferral tiers, the catch-up amounts, and the $360,000 compensation cap under IRC §401(a)(17), while combined employee and employer additions stay capped at $72,000 under IRC §415(c).1
The tool doesn't model vesting schedules, plan-specific match rules, taxes on withdrawals, a job change mid-projection, or a market downturn during your working years. We recheck these statutory figures against IRS guidance every year rather than carrying last year's numbers forward.
Frequently asked questions about 401(k)s
How much should I contribute to my 401k?
Most guidance lands somewhere between 10% and 15% of pre-tax income, including whatever your employer kicks in. The floor is whatever gets you the full match; leaving free money on the table rarely makes sense. If you're starting later in your career, a higher rate closes the gap faster, and the calculator above shows exactly what any given rate compounds to by your target retirement age.
How does an employer match work on a 401k?
Employer match money sits on top of whatever you put in yourself, governed by a formula such as "50% of what you contribute, up to 6% of salary." Put in that 6%, and your employer tacks on another 3%, so 9% of your salary ends up in the account each pay period without costing you a dime extra.
What is the 401k limit for 2026?
The elective deferral limit is $24,500 for 2026. Turn 50 and you can add an $8,000 catch-up for $32,500 total; land in the 60-through-63 window instead, and that catch-up jumps to $11,250, bringing the total to $35,750.
What is a good rate of return for a 401k calculator?
Historically, US stock market averages have run 7% to 10% before inflation over long stretches. Most conservative planning models pull that back to 6% to 8%, though the right number for you depends on your stock-to-bond mix and how far out you're projecting.
Should I choose a Traditional 401k or a Roth 401k?
It depends mostly on which side of the tax bill you'd rather deal with. A traditional 401(k) lowers what you owe today and taxes the withdrawals later; a Roth 401(k) flips that, taxing contributions now so qualified withdrawals come out tax-free down the road. The Roth side tends to favor anyone who expects a higher tax rate in retirement than they're paying today.
What happens to my 401k if I change jobs?
You've got four options: leave the balance where it is, roll it into your new employer's 401(k), roll it into an IRA, or cash it out. That last one is the expensive choice before 59½, since it triggers ordinary income tax plus a 10% early withdrawal penalty on top.
Nicolas Straut
Personal finance writer, former Forbes contributor and This Week in Fintech writer
Sources
- https://www.irs.gov/pub/irs-drop/n-25-67.pdf
- https://www.federalregister.gov/documents/2024/07/19/2024-14542/required-minimum-distributions
- https://pages.stern.nyu.edu/adamodar/New_Home_Page/datafile/histretSPX.html
- https://www.law.cornell.edu/uscode/text/26/415
- https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-tax-on-early-distributions