How to use the 401(k) calculator
- Enter your age, the age you plan to retire and your current 401(k) balance.
- Add your salary and the percentage of pay you contribute.
- Enter your employer's match, for example 50% of what you put in, up to 6% of salary.
- Adjust expected raises, investment return and inflation to test different scenarios.
How it's calculated
For each year until retirement:
- Your contribution = salary × your contribution %, capped at the IRS limit for your age if the limit option is on
- Employer match = salary × min(your %, match cap %) × match rate
- New balance = previous balance × (1 + return) + your contribution + employer match
Your salary grows by the raise you enter each year. For 2026 the IRS employee limit is $24,500, plus an $8,000 catch-up at age 50 or older, or $11,250 at ages 60 to 63. The calculator holds these limits at 2026 levels, which is conservative because they usually rise with inflation. The inflation-adjusted figure divides the result by (1 + inflation)years.
Example
A 30-year-old earning $70,000 with $25,000 saved contributes 8% of pay, and the employer matches 50% up to 6%. With 3% yearly raises and a 7% return, the 401(k) could reach about $1,780,000 by 65. The employer adds roughly $127,000 of that, and in today's dollars (2.5% inflation) the total is worth about $750,000.
Tips
- Always contribute at least enough to get the full employer match. It's an instant 50% to 100% return.
- Raise your contribution by 1% each year, or whenever you get a raise, until you reach 15% or more.
- Check your plan's fund fees. A 1% difference in fees can cost tens of thousands of dollars over a career.
- At 50 and older, catch-up contributions let you save thousands more each year.
Frequently asked questions
How much can I contribute to a 401(k) in 2026?
What is a good 401(k) contribution rate?
How does an employer match work?
Traditional or Roth 401(k)?
What return should I assume?
Related calculators
Sources
- IRS: 401(k) limit increases to $24,500 for 2026
- IRS: Retirement topics - catch-up contributions
- Investor.gov: Compound interest calculator
This calculator provides educational estimates only and is not financial, tax, legal or investment advice. Results depend on the assumptions you enter; actual terms from lenders, insurers and tax authorities may differ.