Retirement Calculator — USA
Find the monthly 401(k)/IRA investment needed to retire in the USA, with 2026 IRS contribution limits and Social Security claiming ages built into the guide below. Free, no signup.
How much do you need to retire in the USA?
Most US retirement income comes from three layers: Social Security, an employer 401(k) (or similar workplace plan) and a personal IRA. Social Security alone is not designed to fully replace a working income, so the gap has to be closed with 401(k)/IRA savings — this calculator estimates the monthly amount you'd need to invest to close that gap, using the "4% rule" (below) as the target corpus.
Social Security: full retirement age and when to claim
Your Social Security full retirement age (FRA) depends on your birth year: it is 66 for anyone born in 1954 or earlier, rises in two-month steps for people born 1955–1959, and is 67 for anyone born in 1960 or later (SSA, accessed 24 September 2026). You can start benefits as early as age 62, but claiming before your FRA permanently reduces the monthly amount. Delaying past FRA increases your benefit by 8% per year (about 2/3 of 1% a month) up to age 70, when the delayed-retirement credit stops (SSA, accessed 24 September 2026). For example, someone with a $2,000 FRA benefit who waits until 70 instead of claiming at 67 could lock in roughly 24% more per month for life — the exact effect depends on your own FRA and earnings record.
2026 401(k) and IRA contribution limits
For the 2026 tax year, the IRS raised the employee contribution limit for 401(k), 403(b) and most 457 plans to $24,500. Savers age 50 and over can add a $8,000 catch-up contribution (total $32,500), and under SECURE 2.0 those aged 60–63 get an enhanced catch-up of $11,250 instead. The IRA contribution limit for 2026 rises to $7,500, with a $1,100 catch-up for those 50 and older (IRS, accessed 24 September 2026). Maxing out an employer 401(k) match before funding an IRA is usually the more efficient order, since the match is an immediate, guaranteed return that no investment can match.
Required minimum distributions (RMD)
Once you reach age 73, the IRS requires you to start taking minimum annual withdrawals from most tax-deferred retirement accounts — traditional 401(k)s, traditional IRAs, SIMPLE and SEP IRAs (IRS, accessed 24 September 2026). Roth IRAs are not subject to RMDs during the original owner's lifetime. Building your retirement plan around your RMD age — not just your target retirement age — matters because withdrawals become mandatory whether or not you need the income that year.
The 4% rule (a rule of thumb, not a guarantee)
- The "4% rule" is a popular rule of thumb, not a law or government guideline: it suggests that withdrawing about 4% of your portfolio in the first year of retirement, then adjusting that dollar amount for inflation each year after, has historically lasted roughly 30 years for a balanced US stock/bond portfolio. It implies a target corpus of roughly 25× your annual expenses.
- It is a planning heuristic, not a promise — actual safe withdrawal rates depend on market returns, your time horizon, and how flexible you can be in a downturn. Treat the 25× figure as a starting point to combine with Social Security and any pension income, not a substitute for professional advice.
- Starting to save earlier dramatically lowers the monthly amount needed, thanks to compounding. The calculator above estimates the monthly 401(k)/IRA investment needed to reach your target.
Frequently Asked Questions
How much do I need to retire in the USA?
There's no single official number — it depends on your target lifestyle, Social Security benefit, and other income. A common starting point is the 4% rule: aim for a portfolio of roughly 25× your expected annual expenses, then adjust for the Social Security income you expect to receive from your full retirement age. The calculator estimates the monthly 401(k)/IRA investment needed to reach a savings target.
What is the 4% rule, and is it official?
No — it's a widely used rule of thumb among financial planners, not an IRS or SSA rule. It suggests withdrawing about 4% of your retirement portfolio in year one, then adjusting for inflation after that, which has historically held up for around 30 years in back-tested US market scenarios. It implies a roughly 25× annual-expenses target corpus.
At what age can I claim Social Security, and when is my full retirement age?
You can claim as early as 62, but your full retirement age (FRA) — when you get 100% of your calculated benefit — is 66 to 67 depending on your birth year (67 for anyone born in 1960 or later, per the Social Security Administration). Claiming before FRA reduces your monthly benefit; delaying past FRA up to age 70 increases it by about 8% a year.
When do I have to start withdrawing from my 401(k) or IRA?
The IRS requires required minimum distributions (RMDs) from most tax-deferred accounts starting at age 73. Roth IRAs are exempt from RMDs during the original owner's lifetime.
Sources
- Social Security Administration — Full Retirement Age by birth year (accessed 24 September 2026)
- Social Security Administration — Delayed Retirement Credits (accessed 24 September 2026)
- IRS Newsroom — 401(k) and IRA limits for 2026 (accessed 24 September 2026)
- IRS — Required Minimum Distributions (RMDs) (accessed 24 September 2026)