If you’ve been waiting for a TSP Roth conversion option inside the Thrift Savings Plan, 2026 is a big deal. Starting in January 2026, the TSP is adding in-plan Roth conversions, also called an in-plan Roth rollover. That means some federal employees and military members will be able to move money from traditional TSP to Roth TSP without leaving the plan.
That sounds great. But here’s the catch: a Roth conversion can create a tax bill right away. For some people, that bill is worth it. For others, it is a costly mistake. The smart move is to run your own numbers before you touch anything. The easiest way to get your exact numbers is to use the free calculator at Is My Job Worth It. You should also watch updates from TSP.gov and the official TSP notice on Roth in-plan conversions coming to the TSP in January 2026.
What TSP Roth 2026 Changes Mean
The basic idea
A traditional TSP gives you a tax break now. Money goes in before income tax. You pay tax later when you take it out.
A Roth TSP works the other way:
- You pay tax now
- The money can grow tax-free
- Qualified withdrawals in retirement are tax-free
A traditional to Roth TSP conversion means you move money already in your traditional balance into your Roth balance. The amount converted is usually taxed as income in the year of the conversion.
One simple way to think about it is this: traditional TSP is “tax later,” while Roth TSP is “tax now.” A conversion is just choosing to switch some money from the “tax later” bucket into the “tax now” bucket.
Why this matters now
Before this change, TSP participants who wanted to convert pre-tax money often had to leave federal service, separate from the military, or move money out to an IRA first. The new TSP Roth 2026 rule gives you a simpler option inside the plan.
That is useful for people who:
- Expect higher tax rates later
- Want more tax-free income in retirement
- Want better control over future taxable withdrawals
- Are trying to reduce future required minimum distributions from traditional balances
It also matters for people who like keeping things simple. Some feds and service members do not want to move money out of TSP just to get one planning feature. Being able to do it inside the plan means fewer steps, fewer accounts to track, and less chance of making a rollover mistake.
If you’re still building your retirement plan, our guides on TSP contribution limits for 2026 and TSP for military members: Roth TSP, BRS matching, and deployment contributions can help you see where conversions fit.
Official sources matter here
Because this is a rule change, details can shift. Check:
A good rule of thumb: use news sites to understand the change, but use TSP and IRS sources before you act.
TSP Roth Conversion Rules: How an In-Plan Roth Rollover Works
What happens during the conversion
Let’s say you have $80,000 in traditional TSP and $20,000 in Roth TSP. If you convert $15,000 from traditional to Roth:
- Your traditional balance drops to $65,000
- Your Roth balance rises to $35,000
- You may owe income tax on the $15,000 this year
The money stays inside TSP. You are not taking cash out for spending. But the IRS still treats the converted amount as taxable income.
Here is the step-by-step version:
- You choose a dollar amount to convert.
- TSP moves that amount from your traditional balance to your Roth balance.
- The converted amount gets added to your taxable income for that year.
- You pay any extra taxes due when you file, or through withholding or estimated payments.
That last part matters more than people think. If you do a large conversion late in the year and do not plan for taxes, you could get an ugly surprise at tax time.
What tax bill could look like
Here’s a simple example.
Assume you are a GS-12 step 5 making $98,000 in taxable wages after pre-tax deductions. You convert $20,000.
Your new taxable income becomes about:
- $98,000
- Plus $20,000 conversion
- Equals $118,000 taxable income before other tax adjustments
If your federal marginal tax rate is 22%, the conversion alone could create about:
- $20,000 × 22% = $4,400 in federal tax
You may also owe state income tax. If your state tax rate is 5%, add:
Total possible added tax:
- $4,400 federal
- $1,000 state
- = $5,400
That is why a conversion is not “free.” It is a tax move, not a magic trick.
Now let’s compare that with a smaller conversion. If the same employee converts only $5,000 instead of $20,000:
- Federal tax at 22%: $1,100
- State tax at 5%: $250
- Total added tax: $1,350
That smaller amount may be much easier to handle from cash savings. It also lowers the risk of bumping into a higher bracket.
Why some people still do it
People choose a TSP tax strategy like this because they want tax-free income later. If that $20,000 grows to $60,000 over time, future qualified Roth withdrawals could be tax-free. In that case, paying tax on $20,000 today may be better than paying tax on $60,000 later.
This can be more attractive if:
- You are in a lower tax bracket this year
- You have a temporary dip in income
- You are early in your career
- You expect a pension plus Social Security plus TSP withdrawals later
There is also a planning benefit here. In retirement, having both traditional and Roth money can give you more control. Need $30,000 one year for a roof, car, or family help? You might take part from traditional and part from Roth to manage taxes.
Federal workers under FERS should think about the full picture. Your pension, Social Security, and TSP all interact. Our guide to Social Security and FERS and FERS retirement calculator article can help with that bigger plan.
Traditional to Roth TSP: Who Might Benefit Most
Early-career federal employees
If you are younger and in a lower tax bracket, a conversion may make more sense. You have more years for tax-free growth.
Example:
- Age 30
- GS-9 salary: about $63,000
- Traditional TSP balance: $25,000
- Converts $10,000
If that $10,000 grows at 7% for 30 years, it could become about $76,000. Paying tax now on $10,000 may be easier to swallow than paying tax later on a much larger amount.
Let’s make that more concrete. If this worker is in the 12% federal bracket and pays 4% state tax:
- Federal tax: $10,000 × 12% = $1,200
- State tax: $10,000 × 4% = $400
- Total tax: $1,600
Paying $1,600 now to potentially get future tax-free access to about $76,000 is why younger workers often look hard at Roth moves.
Military members with lower-tax years
This is a big one. Service members can have unusual tax years because of deployments, special pays, and changing duty status. Some years are much better for a conversion than others.
For example, an E-5 with 6 years of service may have base pay around the mid-$40,000 range in 2026, but taxable income can vary based on allowances and any tax-free combat zone income. If taxable income is lower than usual, converting part of a traditional TSP balance may cost less in taxes.
Here’s a simple compare case:
- Year 1 taxable income: $38,000
- Year 2 taxable income: $58,000
If that service member converts $10,000 in Year 1 while in a 12% bracket, federal tax may be about $1,200. If they wait and convert in Year 2 while in a 22% bracket, federal tax may be about $2,200. Same conversion amount, but about $1,000 more in federal tax just because of timing.
Military families should also compare this with other cash needs like housing, debt, and emergency savings. If you need help seeing your whole pay picture, our 2026 military pay raise guide and BAH calculator 2026 article are useful.
People close to retirement can still benefit
A conversion is not only for younger workers. It can help near retirement too, but the math gets tighter.
You might benefit if:
- You plan to delay Social Security
- You expect large required minimum distributions later
- You have a few low-income years between retirement and age 73
- You want more tax flexibility for healthcare costs or Medicare planning
Example: a federal employee retires at 60, starts the FERS pension, but delays Social Security until 70. Between 60 and 70, taxable income may be lower than it will be later once Social Security starts. That gap can be a useful window for smaller Roth conversions.
For retirees, taxes can affect Medicare premiums too. A large conversion can raise income enough to trigger higher Part B and Part D premiums later. Read our IRMAA guide for retirees before doing a big conversion.
In-Plan Roth Rollover Scenarios With Real Numbers
Scenario 1: GS employee in a moderate tax bracket
Maria is a GS-11 making $82,000. She has:
- $120,000 traditional TSP
- $15,000 Roth TSP
- No state income tax
She converts $12,000 in 2026.
Estimated added federal tax if she is in the 22% bracket:
If that $12,000 grows for 20 years at 6%, it could become about $38,500.
If Maria leaves it in traditional TSP, she pays tax later on withdrawals. If she converts now, she pays tax on $12,000 now and may get tax-free withdrawals later on the full future amount.
What if Maria converts $24,000 instead? Her rough federal tax cost at 22% would be about $5,280. That may still work on paper, but only if she has the cash to cover it and it does not push part of her income into a higher bracket.
Scenario 2: Married federal employee near retirement
James is 59 and plans to retire at 62. He and his spouse have taxable household income of $140,000. He has:
- $400,000 traditional TSP
- $50,000 Roth TSP
He wants to convert $80,000 in one year.
That could be a problem. Why?
- $80,000 added income may push part of the conversion into a higher tax bracket
- It could raise state taxes
- It may affect Medicare IRMAA later if he is already close to those thresholds
A smarter move may be smaller conversions over several years, like:
- $20,000 in 2026
- $20,000 in 2027
- $20,000 in 2028
- $20,000 in 2029
That spreads out the tax hit.
If James is in the 24% bracket and pays 5% state tax, one $80,000 conversion could mean roughly:
- Federal tax: $19,200
- State tax: $4,000
- Total: $23,200
If he spreads it out with four $20,000 conversions, each year’s rough added tax might be:
- Federal tax: $4,800
- State tax: $1,000
- Total: $5,800 per year
Same total conversion amount, but easier to manage and less likely to create other tax problems.
Scenario 3: Active-duty member with a low-tax window
A Staff Sergeant has a $30,000 traditional TSP balance and expects a lower-tax year due to a mid-year transition and lower civilian income after separation.
He converts $8,000.
If his federal marginal tax rate is 12% and state tax is 3%:
- Federal tax: $8,000 × 12% = $960
- State tax: $8,000 × 3% = $240
- Total tax: $1,200
That may be a solid deal if he expects to be in the 22% bracket later in a civilian job.
Scenario 4: Senior fed with a pension coming soon
A GS-14 age 57 has $600,000 in traditional TSP and expects a solid FERS pension. She retires at 60 and expects pension income of about $38,000 a year before Social Security.
If she waits until after retirement and then converts $25,000 during a lower-income year, she may pay less tax than if she converted while still earning a six-figure salary. A lot of people miss this point: the best conversion year may be after you stop working, not while you are still at peak pay.
This is where using Is My Job Worth It can save a lot of time. You can compare your pay, taxes, and future income choices instead of guessing.
Common TSP Roth Conversion Mistakes
The biggest mistake is thinking a conversion means “free tax-free money.” It does not. You are prepaying taxes.
Other common mistakes include:
- Converting too much in one year. This can push you into a higher bracket.
- Forgetting state taxes. Federal tax is only part of the bill.
- Using TSP money to pay the tax. That shrinks retirement savings.
- Ignoring Medicare effects. Big conversions can raise future IRMAA costs.
- Not looking at the full retirement picture. Pension, Social Security, and TSP all work together.
- Assuming Roth is always better. Sometimes traditional is the better deal, especially if your retirement tax rate will be lower.
Here’s another easy-to-miss mistake: converting without an emergency fund. If you owe $4,000 in extra taxes but then your car dies or you PCS, that conversion can create stress fast.
For a broader retirement planning check, our article on mistakes federal employees make before retirement is worth a read.
How to Decide if a TSP Roth 2026 Conversion Makes Sense
Step 1: Find your current tax bracket
Look at your latest tax return and current pay. Estimate your 2026 taxable income.
Ask:
- What is my federal bracket now?
- Do I pay state income tax?
- Am I likely in a lower bracket this year than later?
Also ask whether your income is steady or changing. A promotion, separation, deployment, spouse job change, or retirement date can all change the answer.
Step 2: Estimate future retirement income
Add up likely income from:
- FERS or military pension
- Social Security
- TSP withdrawals
- Other savings
If you need help with pension planning, start with our retirement topic guides and pay info section for linked tools and explainers.
A quick example helps. Say you expect:
- FERS pension: $32,000
- Social Security: $24,000
- TSP withdrawals: $25,000
That is about $81,000 a year before counting a spouse’s income or other savings. If your retirement income may be close to or above your current taxable income, paying some tax now through a conversion may make sense.
Step 3: Test a small conversion first
Instead of converting $50,000 all at once, test smaller amounts:
See how each amount changes your taxes.
For example, if a $5,000 conversion adds about $1,100 in total tax, but a $15,000 conversion adds $3,300 and pushes you near a bracket line, the smaller amount may be the better choice.
Step 4: Make sure you can pay the tax from cash
This matters a lot. The best setup is paying the tax from savings, not from retirement funds.
If you convert $10,000 and owe $2,200 in tax, try to pay that $2,200 from cash on hand.
If you cannot do that comfortably, ask yourself a simple question: if this conversion is a good idea, is it still a good idea right now? Sometimes the answer is “wait until I have more cash.”
Step 5: Check official TSP and IRS guidance
Before acting, confirm the current rules at:
News outlets like FedWeek, GovExec, and Federal Times can help explain updates, but the official rule details should come from TSP and IRS.
Step 6: Run your own numbers
This is the step most people skip. Don’t.
Use Is My Job Worth It to see your personal results. It is the fastest way to compare tax impact, income, and whether this move helps or hurts in your exact case.
Step 7: Ask a few “what if” questions
Before you convert, walk through these:
- What if I get promoted next year and move into a higher bracket?
- What if I retire next year and my income drops?
- What if I move from a no-tax state to a state with income tax?
- What if I need cash for a move, medical bill, or home repair?
- What if a smaller conversion gives me most of the benefit with less risk?
Those questions can save you from making a move that looks smart in general but is not smart for your timing.
Common Questions About TSP Roth Conversion Rules
Can I convert my whole traditional TSP balance?
Maybe, but that does not mean you should. A full conversion can create a huge tax bill. Someone with a $200,000 traditional balance who converts it all in one year could add $200,000 to taxable income. For most people, that is far too much for one tax year.
Is a Roth conversion better than just making new Roth TSP contributions?
Sometimes. New Roth contributions spread the tax cost over time. A conversion creates a tax bill now. Many people may be better off doing both in small amounts instead of making one big move.
What if I am stationed in a state with no income tax?
That can help. If you convert while legally in a no-tax state, you may avoid state income tax on the conversion. On a $15,000 conversion, avoiding a 5% state tax saves about $750.
What if I already have both traditional and Roth TSP?
That is actually common. In that case, the question is not “Roth or traditional?” It is “should I move more of my traditional balance into Roth this year?”
Bottom Line on TSP Roth Conversion Rules for 2026
The new in-plan Roth rollover option is a useful change. It gives federal employees and military members more control inside the TSP. But a traditional to Roth TSP move only helps when the tax math works in your favor.
Here’s the simple version:
- Good for some people in lower-tax years
- Risky if it pushes you into a higher bracket
- Best used as part of a bigger TSP tax strategy
- Usually smarter when done in smaller, planned amounts
Do not convert just because Roth sounds better. Convert because your numbers say it is better. Start with official guidance from TSP.gov and IRS.gov, then try the calculator to see your personal results at Is My Job Worth It.