About this calculator
A 401(k) is an employer-sponsored retirement account with pre-tax contributions and (usually) an employer match. The match is the most valuable financial benefit most US workers ever get — often a 50% or 100% immediate return on every contributed dollar up to the match limit. This calculator projects your balance accounting for contributions, employer match, salary growth, and investment returns over time.
Contribution limits (2024)
- Employee elective deferral: $23,000 ($30,500 if 50+)
- Combined employee + employer + after-tax: $69,000 ($76,500 if 50+)
- Annual limits are indexed to inflation and rise slightly each year.
The match math you can't ignore
A common match: 100% of the first 3%, then 50% of the next 2% — effectively 4% from the employer if you contribute at least 5%. On an $80k salary, that's $3,200 of free money you forfeit by not contributing enough. Always contribute at least to the full match before any other investing.
Traditional vs Roth 401(k)
Traditional: pre-tax contributions, taxable withdrawals. Roth: after-tax contributions, tax-free withdrawals. The right choice depends on whether you expect higher or lower marginal tax rate in retirement. Most high-income mid-career workers should default to traditional; low-income early-career workers should default to Roth. Splitting between both hedges the bet.
Common mistakes
Not contributing enough to capture the full match. Holding too much company stock (single-stock concentration risk plus job correlation). Investing in old, expensive target-date funds inside the plan instead of low-cost index alternatives if available. Cashing out at job changes (massive tax + penalty hit) instead of rolling to an IRA.