Where to Find Tax-Deferred Pension on Form 1040

On Form 1040, a tax-deferred pension distribution is reported on Lines 5a and 5b: the gross payment goes on Line 5a and the taxable portion on Line 5b. If the money came from a Traditional, Roth, SEP, or SIMPLE IRA instead, use Lines 4a and 4b. And if you’re asking because you’re looking for your 401(k) or 403(b) contributions, those don’t appear on a line of their own; they’ve already been subtracted from the W-2 wages you enter on Line 1a.

Pension and Annuity Distributions: Lines 5a and 5b

Payments from an employer-sponsored pension, a 401(k) in payout, or a non-IRA annuity all land on the same two lines. Line 5a shows the gross distribution. Line 5b shows the taxable amount.¹

The gross figure comes straight from Box 1 of the Form 1099-R your plan administrator sends in January.² If you never contributed after-tax dollars to the plan, every dollar coming out is taxable, and the same number goes on both 5a and 5b. That’s the typical pattern for a traditional defined-benefit pension funded entirely by the employer and by pre-tax deferrals.

If you did put after-tax money into the plan at some point, you have a “cost basis” there. The IRS doesn’t tax that portion again when it comes back to you, so Line 5b will be smaller than Line 5a. Two methods are used to split out the tax-free piece:¹

The Simplified Method, for distributions from qualified plans such as 401(k)s and 403(b)s, spreads your after-tax cost across a set number of expected payments and gives you a fixed monthly exclusion until the basis is fully recovered.
The General Rule, for nonqualified annuities, uses an actuarial calculation explained in IRS Publication 939.

When Box 2a on Your 1099-R Is Blank

Sometimes the taxable amount in Box 2a is empty and Box 2b (“Taxable amount not determined”) is checked. That means the plan administrator didn’t do the math for you.³ Run the Simplified Method or General Rule yourself using Box 1 (gross distribution) and Box 5 (your employee contributions), and put the result on Line 5b. Don’t leave 5b blank, and don’t just copy Box 1 if you have after-tax basis in the plan — you’d be paying tax a second time on money you already paid tax on.

IRA Distributions: Lines 4a and 4b

IRA money comes out on a different pair of lines. Line 4a is the gross distribution; Line 4b is the taxable amount.⁴ This covers Traditional, Roth, SEP, and SIMPLE IRAs.

If every Traditional IRA contribution you ever made was deductible, the full distribution is taxable and Lines 4a and 4b match. If you made nondeductible contributions along the way, part of the account is already after-tax, and you need Form 8606 to figure out the taxable portion. The IRS treats all your Traditional IRAs as a single pool, so you can’t segregate the nondeductible dollars into one account and pull them out tax-free. Form 8606 applies a proportional calculation based on your total basis divided by the total year-end value of all your Traditional IRAs. Failing to file Form 8606 when you should carries a $50 penalty, and overstating your nondeductible contributions brings a $100 penalty.⁵

Qualified Roth IRA distributions are fully tax-free. The gross still appears on Line 4a, but Line 4b is zero.⁴ A distribution counts as qualified if the Roth has been open at least five years and you’re 59½ or older, disabled, or taking up to $10,000 for a first home. Earnings pulled out before meeting those tests can be taxable and may also trigger the 10% early withdrawal tax.

Why 401(k) and 403(b) Contributions Don’t Have Their Own Line

If you’re hunting for the line that shows your 401(k), 403(b), government 457(b), or SIMPLE IRA salary deferrals, there isn’t one. The tax deferral happens on the payroll side: your employer takes those pre-tax contributions out before calculating Box 1 of your W-2, so the wages number you enter on Form 1040, Line 1a is already reduced.⁶⁷

Your deferral still appears on the W-2, but in Box 12 with a letter code identifying the plan: Code D for 401(k), Code E for 403(b), Code G for 457(b), Code S for SIMPLE IRA, and Codes AA, BB, and EE for designated Roth contributions to 401(k), 403(b), and government 457(b) plans respectively.⁸ Box 12 is informational, so the IRS can verify you stayed within deferral limits. You don’t carry the Box 12 amount anywhere on the 1040.

Deductible Contributions Flow Through Schedule 1 to Line 10

When you contribute directly to a Traditional IRA or to a self-employed retirement plan, the deduction isn’t baked into a W-2. You claim it as an adjustment to income on Schedule 1, and the Schedule 1 total feeds Line 10 of the 1040.⁹

Traditional IRA deduction: Schedule 1, Line 20. The deduction can be reduced or eliminated based on your modified AGI, filing status, and whether you or your spouse are covered by an employer retirement plan. Check the current IRS phase-out thresholds before filing.¹⁰
SEP IRA, SIMPLE IRA, and solo 401(k) contributions for the self-employed: Schedule 1, Line 16. These are calculated from net self-employment earnings.¹⁰

All Part II adjustments on Schedule 1 are totaled on Line 26 and move to Form 1040, Line 10. The 1040 subtracts Line 10 from total income on Line 9 to produce adjusted gross income on Line 11.⁹

Your IRA custodian sends Form 5498 to you and the IRS documenting your contributions.¹¹ You don’t file it with your return, but keep it. It usually arrives in late May, because custodians wait until after the April contribution deadline.

Rollovers Still Have to Be Reported

Moving money between retirement accounts through a rollover is a reportable event even though no tax is owed. The gross distribution goes on Line 4a for IRA-to-IRA rollovers or Line 5a for employer plan rollovers, and the taxable amount on Line 4b or 5b is zero as long as the transfer finished within 60 days.¹²

To mark the transaction as nontaxable, check the rollover box on Line 4c (or the corresponding spot for Line 5) and write “Rollover” in the entry space.⁶ One thing to watch: if your plan withheld 20% during the rollover and you didn’t replace that amount from other funds within 60 days, the withheld portion counts as a taxable distribution. You’d still report the full gross on Line 4a or 5a, but the shortfall becomes taxable on Line 4b or 5b.¹³

Quick Reference

Line 1a: Wages from W-2 Box 1, already reduced by 401(k)/403(b)/457(b) deferrals.
Line 4a: Gross IRA distributions (Traditional, Roth, SEP, SIMPLE).
Line 4b: Taxable IRA distributions.
Line 4c: Checkbox and entry space for rollover, QCD, or other codes.
Line 5a: Gross pension and annuity distributions.
Line 5b: Taxable pension and annuity distributions.
Line 10: Total adjustments from Schedule 1, including deductible IRA and self-employed plan contributions.
Line 11: Adjusted gross income.
Schedule 1, Line 16: Self-employed SEP, SIMPLE, and qualified plan deduction.
Schedule 1, Line 20: Traditional IRA deduction.
Schedule 2, Line 8: 10% early withdrawal penalty, when it applies.¹⁴

1
Internal Revenue Service. Publication 575 (2025), Pension and Annuity Income
2
Internal Revenue Service. Instructions for Form 1040 – Section: Lines 5a, 5b, and 5c
3
Internal Revenue Service. Instructions for Forms 1099-R and 5498
4
Internal Revenue Service. Publication 590-B, Distributions from Individual Retirement Arrangements (IRAs)
5
Internal Revenue Service. 2025 Instructions for Form 8606
6
Internal Revenue Service. Instructions for Form 1040
7
Internal Revenue Service. Form 1040, U.S. Individual Income Tax Return (2025)
8
Internal Revenue Service. 2026 General Instructions for Forms W-2 and W-3
9
Internal Revenue Service. Adjusted Gross Income
10
Internal Revenue Service. 2025 Schedule 1 (Form 1040)
11
Internal Revenue Service. About Form 5498, IRA Contribution Information (Info Copy Only)
12
Internal Revenue Service. Topic No. 413, Rollovers From Retirement Plans
13
Internal Revenue Service. Rollovers of Retirement Plan and IRA Distributions
14
Internal Revenue Service. Topic No. 558, Additional Tax on Early Distributions From Retirement Plans Other Than IRAs