Take a taxable 401(k) distribution before age 59½ and IRC §72(t) / IRS Topic 558 usually add a 10% additional tax. It sits on top of ordinary federal income tax.
$10,000 at age 45: additional tax $1,000. Amount left after only that penalty: $9,000. Same $10,000 at 59½: additional tax $0.
Run the 401(k) early distribution calculator →
Ordinary FIT still applies. State tax may apply. Code exceptions (rule of 55, SEPP, qualified birth or adoption, and others) are not modeled. A loan that stays a loan is not this tax. Estimate, not tax advice.
Direct answer: $10,000 at 45 → $1,000
- Age 45 is before 59.5
- Additional tax = 10% × $10,000 = $1,000.00
- After that penalty only = $9,000.00
if age < 59.5 → additional tax = distribution × 10% if age ≥ 59.5 → additional tax = $0 net after penalty (excluding ordinary tax) = distribution − additional tax
Checks you can re-run
| Distribution | Age | Early? | 10% tax | After penalty only |
|---|---|---|---|---|
| $10,000 | 45 | Yes | $1,000.00 | $9,000.00 |
| $10,000 | 59.5 | No | $0.00 | $10,000.00 |
| $25,000 | 40 | Yes | $2,500.00 | $22,500.00 |
If the plan pays the money to you instead of a direct rollover, it may also withhold 20%. That is 401(k) rollover withholding, not this 10%. Borrowing instead of taking a distribution is 401(k) loan max.
What this is not
- Not ordinary income-tax withholding or your Form 1040 bracket.
- Not the 20% mandatory withholding on an eligible rollover paid to you.
- Not a hardship worksheet. Hardship can still be taxable and can still owe the 10%.
- Not an IRA early-withdrawal guide, even though §72(t) also touches IRAs.
No. For $10,000 at 45 this page estimates $1,000 extra. FIT is still due on the taxable amount.
The engine returns $0 of the 10% on the same distribution.
Sometimes, under the rule of 55 for a qualified plan. Not modeled. Do not treat $1,000 as your answer if you qualify for an exception.