Roth vs Traditional IRA at $100,000 income: the 22% bracket decision
At $100,000 income, a single filer sits squarely in the 22% federal bracket. The Traditional deduction saves $1,540 in current tax per $7,000 contribution. The Traditional IRA deduction phase-out for workplace-plan participants bites at $79K to $89K single (2026), so most $100K earners with a 401(k) cannot deduct a Traditional IRA contribution anyway. The Roth IRA remains fully eligible up to $150K single. Tax diversification across Roth and pre-tax 401(k) is the standard answer.
The arithmetic at $100K single
2026 single filer with $100,000 wages, standard deduction $15,750, taxable income $84,250. The 22% bracket runs from $48,475 to $103,350 of taxable income (IRS Notice 2024-80). Our $84,250 sits cleanly in the 22% bracket.
A deductible Traditional contribution of $7,000 saves $1,540 in federal tax. State tax at 5% would add another $350, for $1,890 combined. The same $7,000 as Roth saves $0 today.
However, deductibility matters. If you have a workplace 401(k), the Traditional IRA deduction phase-out at $79K to $89K single (2026) eliminates the deduction at $100K MAGI. So in the most common case (W-2 worker with a 401(k)), the Traditional IRA contribution at $100K is non-deductible. It still grows tax-deferred, but no current-year deduction. The choice at $100K is therefore usually between Roth IRA (full eligibility, tax-free growth and withdrawals) and non-deductible Traditional IRA (no current-year deduction, tax-deferred growth, taxable withdrawal at ordinary rates).
Roth wins this comparison decisively. The only reason to make a non-deductible Traditional contribution is as a stepping stone to a backdoor Roth conversion (when your income is above the Roth direct-contribution phase-out). At $100K single you are below the phase-out and have no reason for the backdoor.
The Traditional IRA deduction phase-out (worked example)
For 2026, the active-participant Traditional IRA deduction phase-out per IRS guidance is $79,000 to $89,000 of MAGI for single filers, and $126,000 to $146,000 for married filing jointly (both spouses covered). For a non-covered spouse where the other spouse is covered, the phase-out is $236K to $246K MFJ (this is the "spousal coverage" rule).
At $100K single MAGI with a workplace plan, your Traditional IRA deduction is completely phased out. Zero deduction. You can still contribute, but it's non-deductible (and tracked separately on Form 8606 for tax-basis purposes).
At $100K MFJ with one spouse covered by a workplace plan, the MFJ phase-out at $126K-$146K is not yet hit. Both spouses can make fully deductible Traditional IRA contributions. At $130K MFJ in the phase-out range, the deduction is partially reduced. At $146K and above, no deduction.
The pragmatic implication for $100K single with a 401(k): the only IRA decision is Roth (yes or no), because Traditional is non-deductible and inferior to Roth in almost every scenario. The answer is Roth, yes. Max it at $7,000.
The 401(k) tax-diversification angle
Most $100K W-2 earners have access to a 401(k) with both pre-tax and Roth deferral options. The total elective deferral limit in 2026 is $23,500 (across pre-tax + Roth combined). This is much larger than the IRA limit of $7,000, so the 401(k) is the main vehicle for tax-diversification decisions.
The classic tax-diversification setup at $100K income: max the Roth IRA outside the 401(k) at $7,000 (Roth bucket). Take the full employer 401(k) match (typically pre-tax, but Roth match is now allowed under SECURE 2.0 §604 and many plans default to pre-tax matching). Top up the 401(k) elective deferral with a mix of pre-tax (for the deduction) and Roth (for the tax-free pool). A common allocation: $7,000 Roth IRA + $10,000 pre-tax 401(k) (for the 22% deduction = $2,200 tax saving) + $6,500 Roth 401(k) for total elective contribution of $16,500 in the 401(k) plus the $7,000 IRA.
This produces a balanced portfolio at retirement: roughly 35-45% Roth and 55-65% pre-tax. The pre-tax bucket fills the standard deduction and the 12% bracket cleanly in retirement. The Roth bucket sits above for tax-free spending without IRMAA impact.
The 401(k) employer match always lands in the pre-tax bucket unless your plan offers the SECURE 2.0 §604 Roth match (still rare in 2026 because plan-document amendments lag). The match itself does not count against your $7,000 IRA limit or your $23,500 elective deferral limit. It is "extra" from the contribution-cap perspective and is a core reason to take the full 401(k) match before any IRA contribution.
The bracket-bridge case for Roth at $100K
At 22% federal bracket plus 5% state, the marginal tax cost of a Roth IRA contribution is 27%. The relevant question is: what is your expected marginal rate at withdrawal?
If you continue earning $100K through your career and retire with a $1.5M pre-tax balance (achievable with $20K/year of pre-tax 401(k) for 30 years at 7%), your first RMD at 73 will be roughly $56,600 (using the Uniform Lifetime Table divisor of 26.5). Add Social Security at ~$36K and your retirement ordinary income is $92,600. Plus any other pre-tax balances. Your retirement bracket is squarely 22% federal, possibly edging into 24%. The Roth contribution at 22% today is roughly bracket-neutral against the retirement-bracket expectation. Roth wins on tie-breakers: tax-free growth, no RMDs, no IRMAA exposure, more flexible estate planning.
If you expect dramatic income growth (career trajectory toward $200K+ by your 40s), the future bracket is 32% or higher. Today's 22% Roth is cheap insurance against future higher brackets. Roth wins decisively.
If you expect to retire to a low-cost area on a tight budget with no pension and modest Social Security, your retirement bracket might dip to 12%. Today's 22% Roth is more expensive than the future 12% Traditional withdrawal. Traditional 401(k) would have been better than Roth IRA in this scenario. The IRA-specific decision still favours Roth IRA over non-deductible Traditional IRA, but the 401(k) decision tilts toward pre-tax.
The decision rule for $100K income
Single filer at $100K with workplace 401(k): Roth IRA. Traditional IRA at this income with a workplace plan is fully non-deductible, which makes Traditional inferior to Roth. Use the $7,000 for Roth IRA. Use the 401(k) for the pre-tax / Roth mix you want.
MFJ at $100K combined with both spouses covered by 401(k): mix of Roth and deductible Traditional possible. At $100K MFJ MAGI, you are below the $126K-$146K MFJ Traditional deduction phase-out, so both spouses can make deductible Traditional contributions. The 12% bracket runs to $96,950 of taxable income for MFJ (2026), so a $100K-gross MFJ couple is mostly in the 12% bracket. Roth still dominates at the 12% bracket level. Use Roth IRA.
Single filer at $100K with no workplace plan: deductible Traditional or Roth both work. Deductible Traditional at 22% saves $1,540. Roth saves $0 today and creates the tax-free pool. For a young saver, Roth still wins. For someone nearing retirement with a clearly lower retirement bracket, Traditional may pull ahead.
Always take the full 401(k) match first. The match is typically a 50% or 100% return on your first 3-6% of salary, far better than any market return. Capture it before any IRA decision.
FAQ
Can I deduct a Traditional IRA contribution at $100K single?
Only if you do NOT have a workplace retirement plan. With a 401(k), TSP, or similar plan, the Traditional IRA deduction phases out from $79K to $89K MAGI single (2026), so at $100K you get zero deduction.
Can I contribute to a Roth IRA at $100K?
Yes, fully. The single Roth IRA phase-out starts at $150K MAGI (2026). At $100K you are well below the phase-out and eligible for the full $7,000 contribution.
Should I do Roth IRA or 401(k) at $100K?
Both. Take the full employer 401(k) match first. Then max the Roth IRA at $7,000. Then return to the 401(k) for additional pre-tax or Roth deferral up to the $23,500 elective limit. This order captures the match, maximises tax-diversification, and uses the IRA's broader fund choice for the Roth portion.
Is non-deductible Traditional IRA worth it at $100K?
Only as a stepping stone to a backdoor Roth conversion. If your income is below the direct Roth contribution phase-out (under $150K single, $236K MFJ for 2026), the direct Roth is simpler and better. The non-deductible Traditional path is for higher earners who need the backdoor route.
What is the tax-diversification argument?
Having both Roth and pre-tax retirement balances lets you control your taxable income year by year in retirement. Pre-tax fills your standard deduction and low brackets. Roth funds anything above without raising AGI (helpful for IRMAA, Social Security taxation, capital gains brackets). The mix gives you more lever to optimise.
Should I always take the 401(k) match before any IRA contribution?
Yes, in nearly every case. A 100% match on the first 3% of salary at $100K is $3,000 of free money. No IRA strategy beats that. Capture it first.
Not financial, tax, or legal advice. Figures sourced from IRS Notice 2024-80 (2026 brackets and phase-outs), IRC §219(g) (active-participant Traditional deduction phase-out), IRC §408A(c)(3) (Roth IRA phase-out), IRC §414(v) (401(k) elective deferral), SECURE 2.0 Act of 2022 §604 (Roth employer match). Tax laws change. Consult a fiduciary financial advisor, CPA, or qualified retirement planner.