How to Estimate 401(k) Growth (2026 Limits Included)
Short answer
Add your yearly contribution and your employer's match, grow the balance by an assumed return each month, and repeat until retirement. A 30-year-old earning $70,000 who saves 10%, gets a 50% match on the first 6% of pay and starts with $20,000 could reach about $1.48 million by 65 at a 6% return with 2% raises, or roughly $625,000 in today's dollars at 2.5% inflation. For 2026 the IRS employee limit is $24,500. Run your own case in the 401(k) calculator.
A 401(k) grows from three sources: what you put in, what your employer adds, and investment returns on both. Because returns compound for decades, small changes in the savings rate or start age make big differences at the end. You can follow along with your own numbers in the free 401(k) calculator, which shows the balance year by year.
What are the 401(k) limits for 2026?
- Employee deferral limit: $24,500.
- Catch-up at age 50+: an extra $8,000, for $32,500 in total.
- Ages 60 to 63: a higher catch-up of $11,250 instead, for $35,750, if your plan allows it.
Employer contributions do not count toward the $24,500 employee limit; they fall under a separate, higher combined limit. Our calculator caps your own contribution at the limit for your age and holds limits at 2026 levels for future years, which is cautious because the IRS usually raises them with inflation.
How does the employer match work?
A common formula is "50% of what you contribute, up to 6% of pay". On a $70,000 salary, contributing at least 6% ($4,200) earns a $2,100 match. Contributing less than 6% leaves part of the match unclaimed, which is like turning down part of your pay. Check your plan's summary plan description for its exact formula and vesting schedule.
Worked example
Inputs: age 30, retire at 65, salary $70,000 rising 2% a year, contribution 10%, 50% match on the first 6%, current balance $20,000, 6% yearly return, 2.5% inflation.
| Item | Estimate (from the calculator) |
|---|---|
| Your contributions over 35 years | β $350,000 |
| Employer match over 35 years | β $105,000 |
| Balance at 65 | β $1,482,500 |
| In today's dollars (2.5% inflation) | β $624,700 |
| 4% rule income, today's dollars | β $2,080 a month |
Investment growth supplies roughly two-thirds of the final balance. That is compounding at work, and it is why starting early matters. The rule of 72 shows money roughly doubles every 12 years at 6%.
What return should I assume?
Nobody knows future market returns. A balanced long-term assumption of 5% to 7% a year before inflation is common in planning, but run a low case (for example 4%) too. Fees matter: a 1% yearly fee on a fund can cut a 35-year result by a large share, so check your plan's expense ratios.
Traditional or Roth 401(k)?
Traditional contributions reduce your taxable income now, and withdrawals are taxed later. Roth contributions are taxed now, and qualified withdrawals are tax free. If you expect a higher tax rate in retirement, Roth can make sense; if lower, traditional. Our federal income tax guide helps you see your current bracket.
How much should I contribute?
- At least enough to get the full employer match.
- Then aim for a total savings rate (you plus employer) that fits your goal; many planners suggest around 15% of pay.
- Raise your percentage by 1 point each year or with each raise.
For the bigger picture, including Social Security and other savings, use the retirement calculator and our guide on how much to save each month. To understand the growth maths itself, see monthly compound interest or the compound interest calculator.
Disclaimer: this guide is general information, not financial, tax, legal or medical advice. ViralScopeHub is not responsible for decisions made using it; rules and rates change, so confirm with the official source or a qualified professional.
Last updated: October 16, 2026, 9:00 AM ET. Reviewed against the sources listed below.
Frequently asked questions
What is the 401(k) contribution limit for 2026?
$24,500 for employee deferrals. Workers 50 and older can add $8,000, and those aged 60 to 63 can add $11,250 instead if the plan allows.
Does the employer match count toward the limit?
Not toward the $24,500 employee limit. Employer and employee money together fall under a separate, higher annual limit.
How much will my 401(k) be worth?
It depends on contributions, match, return and time. A 30-year-old saving 10% of $70,000 with a 50% match up to 6% could reach about $1.48 million at 65 at a 6% return.
What return should I use in a 401(k) calculator?
Use a range. Many planners test 4% to 7% a year before inflation. Returns are not guaranteed.
What is the 4% rule?
A rule of thumb that withdrawing about 4% of a balance in the first year of retirement, then adjusting for inflation, has historically lasted around 30 years. It is a guide, not a guarantee.
