US 401(k) Retirement Calculator

US 401(k) Guide

What's the key thing to understand about 2025 Contribution Limits?

401(k) employee contribution limit 2025: $23,500. Catch-up contribution if age 50+: additional $7,500 (total $31,000). New for 2025: catch-up for ages 60-63 is $11,250 (instead of $7,500) under SECURE 2.0 Act. Employer match does NOT count toward the $23,500 limit — it's a separate $46,000 combined limit. Most people don't contribute the max — the median 401(k) contribution rate is 7-8% of salary. Best practice: contribute AT LEAST enough to get full employer match (free money), then increase 1%

What's the difference between Roth and Traditional 401(k)?

Traditional 401(k): contribute pre-tax, money grows tax-deferred, withdrawals in retirement taxed as ordinary income. Reduces current year taxable income. Best when current tax bracket is HIGH and you expect to be in a LOWER bracket in retirement. Roth 401(k): contribute post-tax, money grows tax-free, withdrawals in retirement are tax-free. Doesn't reduce current taxable income. Best when current tax bracket is LOW and you expect to be in a HIGHER bracket in retirement. Young workers often benefit most from Roth contributions, since their current tax bracket tends to be lower than what they're likely to face once income and tax rates rise later in their careers.

What do I need to know about Employer Match — The Most Important Rule?

Always contribute enough to capture the full employer match. Common match structures: 50% of contributions up to 6% of salary (most common — equals 3% additional from employer). 100% of contributions up to 3% of salary. 100% on first 3% + 50% on next 2%. Calculating the real value: at $75,000 salary with 50% match on first 6%, you contribute $4,500/year, employer contributes $2,250/year. Over 35 years at 7% return, that $2,250/year of employer money grows to approximately $311,000. By contrast, an employee who contributes nothing forfeits that entire match permanently — it's effectively free money left on the table with no way to claim it retroactively.

What do I need to know about The 4% Rule and Retirement Withdrawals?

The Trinity Study (1998, updated regularly) suggests that retirees can safely withdraw 4% of their starting portfolio in year one, adjusting for inflation each year, with 95%+ probability of the money lasting 30 years. Translation: every $1 million in retirement savings provides approximately $40,000/year sustainable income. A 25-year-old saving $500/month at 7% reaches $1.2M by 65 — providing $48,000/year retirement income, supplementing Social Security, which averages around $24,000/year, and any other retirement income sources like a pension or part-time work.