US retirement accounts: the complete guide

The US retirement system stacks tax-advantaged accounts in a particular order — and getting the order right is the single biggest lever most people have over their long-run net worth. This guide covers every account that matters in 2025 and 2026, with the SECURE 2.0 and One Big Beautiful Bill Act (OBBBA) changes that landed in the last twelve months flagged clearly.

Employer plans: 401(k), 403(b), 457, TSP

The workhorse accounts. Employees can defer $24,500 of salary in 2026 (up from $23,500 in 2025), with a $8,000 catch-up at age 50+. SECURE 2.0 added a separate “super catch-up” of $11,250 for ages 60-63 — bringing the 2026 maximum personal contribution to $35,750 for someone in their early 60s.

Employer matches don't count against your $24,500 personal limit, but they do count against the overall §415(c) defined-contribution ceiling of $72,000 (2026). Always take the full match — it's an instant 50% or 100% return on the money you put in.

IRAs: Traditional and Roth

Traditional IRA contributions may be deductible (depending on whether you're covered by a workplace plan and your income), with withdrawals taxed in retirement. Roth IRA contributions are after-tax with tax-free qualified withdrawals — better when you expect to be in a higher bracket later, or when you want tax-diversification across pre-tax and post-tax pots.

Backdoor and mega backdoor Roth

The backdoor Roth sidesteps the Roth IRA income limits: contribute $7,500 to a nondeductible Traditional IRA, then convert it to Roth (reported on Form 8606). Watch the pro-rata rule — the IRS aggregates all your Traditional, SEP and SIMPLE IRA balances when calculating the taxable portion. If you have $93k of pre-tax IRA money and add $7.5k nondeductible, about 92.5% of any conversion is taxable. The fix is to roll pre-tax IRAs into a 401(k) first, where the pro-rata calculation doesn't reach them.

The mega backdoor Roth moves much bigger money. If your 401(k) plan allows after-tax contributions and either in-plan conversions or in-service distributions, you can add up to $47,500 a year (2026 §415 cap of $72k minus your $24,500 deferral, reduced by employer match), convert it to Roth, and watch it grow tax-free. Few plans allow both steps; check yours.

The HSA: triple tax-advantaged

If you're on a qualifying High-Deductible Health Plan, the HSA beats every retirement account on tax efficiency:

• Contributions are deductible above the line (and avoid FICA when made through payroll).
• The money grows tax-free.
• Qualified medical withdrawals are tax-free — at any age.

After 65 the HSA effectively becomes a stealth Traditional IRA: non-medical withdrawals are taxed as ordinary income but escape the 20% penalty, while medical withdrawals stay tax-free. See our dedicated HSA article for the spend-vs-save question.

RMDs after SECURE 2.0

Required Minimum Distributions start at age 73 for people born 1951-1959 and at 75 for those born in 1960 or later (effective 2033). The first RMD is due by April 1 of the year following the trigger age. Roth IRAs never require RMDs from the original owner; Roth 401(k)s lost their RMD requirement on 1 January 2024. Miss an RMD and you face a 25% excise tax, reduced to 10% if you fix it within two years.

Roth conversions

A Roth conversion turns pre-tax IRA dollars into Roth dollars by paying ordinary income tax on the converted amount today. The right time is usually a low-income year — pre-Social Security, between jobs, or after a big charitable deduction. Watch the side effects: bracket creep, the Medicare IRMAA premium surcharge two years later, and the NIIT on other investment income. Each conversion starts its own five-year clock for the 10% early-withdrawal penalty on principal — separate from the original Roth five-year rule for earnings.

Self-employed plans