Where to Find Tax-Deferred Pension on Form 1040

Tax-deferred pension income appears on Form 1040 on Lines 5a and 5b. Line 5a shows the gross distribution you received from the pension or annuity, and Line 5b shows the portion that is actually taxable.¹ Both numbers come off Form 1099-R, which your plan administrator mails each January.

Filling In Lines 5a and 5b From Your 1099-R

The gross distribution in Box 1 of the 1099-R goes on Line 5a. The taxable amount in Box 2a goes on Line 5b.² If you never put after-tax money into the plan, the two figures match: the whole distribution is taxable, and the same number lands on both lines. That is the situation for most people receiving a traditional defined-benefit pension.

A quick sanity check before you copy anything over: confirm the payer name, your Social Security number, and the distribution codes in Box 7. Those codes tell the IRS what kind of distribution this is (normal retirement, early withdrawal, rollover, disability, and so on), and they drive whether penalties or exceptions apply later on the return.

When Box 2a Is Blank

Some 1099-Rs arrive with Box 2a empty and Box 2b (“Taxable amount not determined”) checked. That means the plan administrator did not compute the taxable amount for you.³ You cannot leave Line 5b blank, and you should not simply copy Box 1 if you have after-tax basis in the plan. You need to run the calculation yourself using Box 1 (gross distribution) and Box 5 (your employee contributions) and enter the result on Line 5b.

When Part of the Pension Is Tax-Free

If you contributed after-tax dollars to the plan while you were working, you have a cost basis. You already paid tax on that money once, so a portion of every payment comes back to you tax-free. The IRS uses one of two methods to figure out how much:¹

Simplified Method, used for qualified employer plans like 401(k)s and 403(b)s. It spreads your after-tax cost across a set number of expected monthly payments, giving you a fixed exclusion each month until you have recovered your full basis.
General Rule, used for nonqualified plan annuities. The actuarial calculation is spelled out in IRS Publication 939.

The tax-free portion reduces your gross payment on Line 5a down to the taxable figure you write on Line 5b. Getting this right matters, because if you enter the gross amount on both lines you will pay tax a second time on money you already paid tax on.

What Does Not Go on Line 5a

Two categories of retirement money look like they belong on Line 5 but do not.

Your ongoing 401(k), 403(b), or government 457(b) contributions never appear on Line 5. Those deferrals were subtracted from your wages before your W-2 was printed, so Box 1 of the W-2 already reflects the reduced amount, and that Box 1 number is what you enter on Line 1a.⁴ Box 12 of your W-2 shows the deferral amount for the IRS to verify against annual limits, but you do not enter Box 12 anywhere on the 1040.⁵

IRA distributions, on the other hand, do get reported, just on different lines. Traditional, Roth, SEP, and SIMPLE IRA distributions go on Lines 4a and 4b, not 5a and 5b.⁶ The 1040 keeps IRAs and employer plans on separate lines even though the tax treatment is similar. If you take money from a 401(k) that has been rolled into an IRA, it goes on the IRA line; if you take it directly from the 401(k) or an employer pension, it goes on Line 5.

Rollovers

Moving money from a pension or 401(k) into another retirement account is not a taxable event, but it still shows up on Line 5. Enter the gross amount on Line 5a and zero on Line 5b, as long as you completed the transfer within 60 days.⁷ Then write “Rollover” in the entry space next to the line so the IRS knows why the taxable portion is zero.⁴

Watch out for withholding. Employer plans generally withhold 20% for federal tax on distributions paid to you directly. If you do not replace that 20% out of pocket when you deposit the money into the new account, the withheld amount counts as a taxable distribution. You would still report the full gross on Line 5a, but the withheld portion becomes taxable on Line 5b.⁸ A direct trustee-to-trustee transfer avoids the 20% withholding problem entirely.

Early Withdrawals Before Age 59½

Taking pension or 401(k) money before age 59½ generally adds a 10% penalty on top of ordinary income tax. The distribution itself still lands on Lines 5a and 5b in the usual way. The extra 10% is reported separately on Schedule 2 (Form 1040), Line 8, and the Schedule 2 total flows back into your tax on the 1040.⁹

If Box 7 of your 1099-R shows distribution code 1, the IRS already knows the penalty applies, and you can enter it on Schedule 2 without any extra forms. If the code is missing or wrong, or if you qualify for one of the exceptions, file Form 5329 to compute the penalty or claim the exemption.⁹

Common exceptions to the 10% penalty include:¹⁰

Separation from service in or after the year you turn 55 (age 50 for public safety employees), for employer plans.
A series of substantially equal periodic payments calculated on your life expectancy.
Total and permanent disability, or a physician-certified terminal illness.
Unreimbursed medical expenses above 7.5% of your AGI.
Qualified birth or adoption expenses, up to $5,000 per child.

Required Minimum Distributions From a Pension

Once you reach the required beginning age, the IRS makes you start pulling money out of tax-deferred retirement accounts each year. Under SECURE 2.0, that age is 73 if you were born between 1951 and 1959, and 75 if you were born in 1960 or later.¹¹ Your first RMD is due by April 1 of the year after you reach that age, and every RMD after that is due by December 31.

An RMD from a pension or 401(k) is reported like any other distribution: gross amount on Line 5a, taxable amount on Line 5b.⁶ There is no separate RMD line and no special notation. It simply adds to your taxable income for the year.

Missing an RMD is expensive. The penalty is 25% of the amount you were supposed to withdraw, dropping to 10% if you correct the shortfall within two years.

Putting It Together

For a straightforward year with one pension check and no complications, filling in Line 5 takes about a minute: copy Box 1 of the 1099-R to Line 5a, copy Box 2a to Line 5b, and move on. The work shows up when there is after-tax basis in the plan, when Box 2a is blank, when a rollover is involved, or when the distribution came out before 59½. In each of those cases, Line 5a still holds the gross amount from Box 1. What changes is Line 5b, whether you need to write a code next to it, and whether Schedule 2 or Form 5329 gets involved.

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. Instructions for Form 1040
5
Internal Revenue Service. 2026 General Instructions for Forms W-2 and W-3
6
Internal Revenue Service. Publication 590-B, Distributions from Individual Retirement Arrangements (IRAs)
7
Internal Revenue Service. Topic No. 413, Rollovers From Retirement Plans
8
Internal Revenue Service. Rollovers of Retirement Plan and IRA Distributions
9
Internal Revenue Service. Topic No. 558, Additional Tax on Early Distributions From Retirement Plans Other Than IRAs
10
Internal Revenue Service. Retirement Topics – Exceptions to Tax on Early Distributions
11
Congress.gov. Required Minimum Distribution (RMD) Rules for Original Owners