How much is the OBBBA senior deduction?

$6,000 per person age 65 or older, for tax years 2025 through 2028. A married couple where both spouses are 65+ can claim $12,000. It phases out starting at $75,000 MAGI single and $150,000 married filing jointly.

Does the senior deduction stack with the standard deduction?

Yes, twice over. It stacks on top of the regular standard deduction and the existing age-65 additional standard deduction, and unlike most extras, itemizers can claim it too.

Did OBBBA really end taxes on Social Security?

No. The provisional income formula and the 85% inclusion rule are unchanged. The senior deduction reduces taxable income after Social Security is counted, which can zero out the tax bill for lower-income retirees. Higher-income federal retirees still see up to 85% of benefits taxed.

Do CSRS retirees get the senior deduction?

Yes, on the same terms. The practical catch is that larger CSRS pensions push many retirees past the $75,000 single phase-out start, shrinking the deduction by $60 for every $1,000 over the line and eliminating it at $175,000.

Does the deduction lower my MAGI for IRMAA?

No. It reduces taxable income, not AGI, so it does nothing for Medicare premium surcharge calculations. A Roth conversion that fits under the deduction phase-out can still trip an IRMAA cliff two years later.

How long does the senior deduction last?

Through tax year 2028. Under current law it disappears January 1, 2029, which makes 2025 through 2028 a four-year planning window for TSP withdrawals and Roth conversions.

The $6,000 Senior Deduction: Federal Retiree Math

Last Updated: August 16, 2026 Reading Time: 8 min

If you're a federal retiree 65 or older, the OBBBA senior deduction is probably worth $1,300 to $2,900 a year to your household through 2028, and you may be planning around the wrong version of it. The "no tax on Social Security" headline isn't what the law does. Here's the actual math for FERS and CSRS retirees.

What You Can Actually Deduct at 65+

Here's the full stack for 2025 returns, using the standard deduction:

Deduction layer	Single, 65+	Couple, both 65+
Standard deduction	$15,000	$30,000
Age-65 additional deduction	$2,000	$3,200
OBBBA senior deduction (under MAGI limits)	$6,000	$12,000
Total sheltered	$23,000	$45,200

The underappreciated detail: the senior deduction isn't part of the standard deduction. A couple who itemizes $35,000 in mortgage interest and state taxes still claims the $12,000 on top. Almost no other retiree tax break works that way.

At the 22% bracket, the full couple deduction saves $2,640 a year. Over the four-year window, that's more than $10,000 for doing nothing but filing correctly.

The Phase-Out Is Where Federal Retirees Get Caught

The deduction shrinks by $60 for every $1,000 of MAGI above the threshold:

Filing status	Full deduction below	Fully gone at
Single	$75,000	$175,000
Married filing jointly	$150,000	$250,000

Now put typical federal retirement income against those lines.

A FERS couple with a $45,000 pension, $40,000 in combined Social Security, and $30,000 in TSP withdrawals sits around $115,000 to $125,000 MAGI. Comfortably under $150,000: full $12,000 deduction.

A single CSRS retiree with an $85,000 pension and no Social Security starts $10,000 over the single threshold before touching savings. That first $10,000 of excess already trims the deduction by $600, and any TSP or IRA withdrawal trims it further. Many CSRS singles land in the partial zone; some lose it entirely.

The law treats FERS and CSRS identically. The pension sizes don't.

The marketing writes a check the statute doesn't cash. The provisional income formula in IRC section 86, the one that pulls up to 85% of your Social Security into taxable income, was not touched. Neither were the 0/50/85 percent tiers or their thresholds.

What actually happens: your Social Security gets included in income exactly as before, and then the senior deduction takes $6,000 or $12,000 back off the top. For a retiree couple with modest income, that reduction can bring the final tax bill to zero, which is where the slogan comes from. For a typical federal retiree household with a pension on top of Social Security, up to 85% of benefits are still taxed. You just pay somewhat less overall.

If you're modeling retirement income around a belief that Social Security became tax-free, redo that math before it costs you a withholding surprise.

The Four-Year Roth Conversion Window, and Its Trap

The 2025-2028 window changes Roth conversion math in a way worth planning deliberately.

The opportunity: a conversion fills up taxable income, and the senior deduction absorbs some of it. A couple converting while staying under $150,000 MAGI keeps the full $12,000 deduction, effectively discounting the conversion's tax cost by up to $2,640 a year at 22%. Do that across four years and the window shelters a meaningful chunk of conversion.

The trap has two jaws. First, conversions count toward MAGI, so an aggressive conversion eats the very deduction that made it attractive: every $1,000 over the line costs $60 of deduction, an effective 6-point surcharge on your marginal rate through the phase-out band. Second, the deduction does nothing for IRMAA. Medicare surcharges key off MAGI with a two-year lookback, and the 2026 Part B cliff for a single filer sits at $109,000. A conversion that looks fine for the senior deduction can still buy you 12 months of higher Medicare premiums starting two years later.

Size conversions against both lines, not just one. The TSP Roth Conversion Calculator models the tax cost, and the IRMAA Cliff Calculator shows how close a planned conversion puts you to a premium cliff. Our Roth conversion IRMAA timing guide walks the two-year lookback in detail.

What to Do Before December 31

Estimate your 2026 MAGI now, while there's still time to shift income. The deduction rewards being $1 under the threshold and punishes being $10,000 over at exactly $600.
If you're under the phase-out with room to spare, consider whether a modest Roth conversion uses that room efficiently inside the four-year window.
If you're in the phase-out band, every marginal dollar of income carries the hidden 6% surcharge. Deferring a discretionary TSP withdrawal into a leaner year may beat taking it now.
If you turn 65 during 2026, you qualify for the deduction for the whole tax year. Factor it into your first Medicare-year budget.
Plan for 2029. The deduction dies with the 2028 tax year under current law. Any strategy that depends on it needs to finish by then.

Model Your Conversion Before You Pull the Trigger

Use the free TSP Roth Conversion Calculator to see the tax cost of a conversion at your income level, then check the result against the senior-deduction phase-out and the IRMAA cliffs before you commit.

Frequently Asked Questions

How much is the senior deduction and who qualifies?

$6,000 per person age 65 or older with a valid Social Security number, for tax years 2025 through 2028. Both spouses qualifying means $12,000 on a joint return. Phase-out starts at $75,000 MAGI single, $150,000 joint.

Does it stack with the standard deduction?

Yes, and with the age-65 additional standard deduction too. Itemizers can also claim it, which is unusual: a 65+ couple on the standard deduction shelters $45,200 of income in 2025.

No. The inclusion formula is unchanged; up to 85% of benefits still count as taxable income for most federal retirees. The deduction reduces taxable income afterward, which zeroes out the bill only at modest income levels.

Do CSRS retirees qualify?

Yes, identically. But bigger CSRS pensions often start past the $75,000 single threshold, so many CSRS retirees get a reduced deduction or none. The phase-out costs $60 per $1,000 of excess MAGI.

Does the deduction help with IRMAA?

No. IRMAA runs on MAGI, and the deduction reduces taxable income downstream of MAGI. Conversions and withdrawals still count fully toward Medicare surcharge thresholds, with the two-year lookback.

When does it expire?

After tax year 2028. Treat 2025 through 2028 as a finite window for withdrawal and conversion planning.

TSP Roth Conversion Calculator: The tax cost of converting at your income level.
IRMAA Cliff Calculator: How close your income sits to a Medicare surcharge cliff.
Roth Conversion IRMAA Timing Guide: The two-year lookback and how to sequence conversions.
OBBBA Tax Guide for Federal Employees: The full law, including the overtime deduction and Trump accounts.

Sources: H.R. 1, Public Law 119-21 (Congress.gov), Bipartisan Policy Center explainer, Thomson Reuters tax analysis, IRS Rev. Proc. 2024-40 (2025 standard deduction figures), Kiplinger 2026 IRMAA brackets.