Pre-tax 401(k) and Traditional IRA contributions reduce your taxable income dollar for dollar. Enter your income and planned contributions to estimate the resulting US federal tax savings.
US 401(k) / IRA Tax Savings Calculator
Estimate the US federal tax savings from pre-tax retirement contributions
* 2026 IRS contribution limits: $24,500 for 401(k), $7,500 for a Traditional IRA. Estimates federal tax only. FEIE, PFIC rules, and IRA deduction income phase-outs for expats aren’t modeled here.
How to Use
- Select your filing status.
- Enter your taxable income before these contributions.
- Enter your planned 401(k) and Traditional IRA contributions (2026 limits: $24,500 and $7,500).
- Click Calculate to see your tax before and after the contributions, and the estimated savings.
How the calculation works
Pre-tax contributions lower your taxable income, so the savings equals the tax on your income before contributions minus the tax on your income after contributions — calculated using the full 2026 progressive bracket schedule rather than a single flat rate, since a large contribution can span more than one bracket.
Tax savings = tax(income) − tax(income − contribution)
Frequently Asked Questions
Q. Why isn’t the savings just my contribution times my tax bracket?
A. A large contribution can span more than one tax bracket — the portion of income it removes from the top bracket saves at that rate, while the portion crossing into a lower bracket saves at the lower rate. This calculator accounts for that by computing tax before and after separately.
Q. Does this apply to a Roth 401(k) or Roth IRA?
A. No. Roth contributions are made with after-tax dollars and don’t reduce current-year taxable income, so this calculator (which estimates the savings from pre-tax contributions) doesn’t apply to them.
Q. Does living in Japan change these US contribution limits?
A. The federal limits themselves don’t change, but Traditional IRA deductibility can phase out at certain income levels if you’re covered by a workplace plan, and interactions with the Foreign Earned Income Exclusion can be complex — this calculator doesn’t model those phase-outs.
Key Takeaways
- 2026 limits: $24,500 for a 401(k), $7,500 for a Traditional IRA.
- Savings are calculated across the full progressive bracket schedule, not a flat rate.
- Roth contributions don’t reduce current-year taxable income and aren’t covered here.