State tax guide
401(k) Rollover in Illinois
Illinois taxes 401(k) distributions as ordinary income at up to 4.95% flat — but retirement distributions are subtracted. A correctly executed direct rollover avoids all state tax. A failed rollover adds Illinois income tax on top of the federal bill.
What Illinois residents need to know
- Illinois has a flat 4.95% income tax, but subtracts federally-taxed distributions from qualified employee plans — including 401(k) plans — and from IRAs on the Illinois return (Publication 120). In practice, a normal 401(k)/IRA distribution is not taxed by Illinois.
- Because the distribution is subtracted, a failed 60-day rollover that becomes federally taxable still generally carries no Illinois income tax — a rare state where a rollover slip costs you federally but not at the state level.
- Illinois explicitly allows the subtraction for early distributions too: Pub 120 states 'You may include early distributions from qualified plans and IRAs.' There is no Illinois age condition.
- A properly completed direct rollover has no Illinois tax consequence, the same as every state.
- Roth conversions are subtractable in Illinois — a traditional 401(k)/IRA-to-Roth conversion that is federally taxable is generally subtracted on the Illinois return (Pub 120 lists IRA amounts 'including amounts rolled over to a Roth IRA').
Watch out for
- The subtraction covers QUALIFIED plan distributions and IRAs. Non-qualified deferred compensation and lump sums using federal 10-year averaging (Form 4972) are NOT subtracted — confirm your distribution type with a CPA if it is unusual.
- Illinois generally does not require withholding on retirement income (Pub 130), so no Illinois tax is withheld even when federal tax is — that is expected, not an error.
Good news
Illinois is one of the most forgiving states for a rollover mistake: because 401(k) and IRA distributions are subtracted from Illinois income regardless of age, a botched rollover typically has zero Illinois tax cost.
The right move for Illinois residents
The most important step is the same in every state: do a direct rollover — custodian-to-custodian, no check issued to you. This eliminates the 20% mandatory federal withholding, the 60-day deadline risk, and all state tax exposure in one step.
The nesthelm plan generates custodian-specific transfer instructions for your exact situation — your custodian, your balance, your destination, and your state. Free preview, $49 full plan.
Free tools for Illinois residents
Custodian guides
State rules are half the picture — the transfer itself runs through your custodian's process.
This guide provides educational information about Illinois state tax rules as applied to 401(k) rollovers. State tax law changes frequently. Verify with a Illinois-licensed CPA before acting on this information.