Roth TSP vs Traditional TSP: Which should you choose?

If you're putting money into your TSP, you've probably hit a choice that feels bigger than it should. Pay taxes now, or pay taxes later? That's the heart of the Roth TSP vs Traditional TSP question.

There's no one right answer for everyone. But there is a right answer for you, and you can find it with a few simple checks.

Let's break this down in plain English. By the end, you'll know how each option works, which one fits your situation, and how to switch.

The Basics: What Roth and Traditional TSP Actually Mean

The TSP is the retirement savings plan for federal employees and service members. It works a lot like a 401(k). You can put your money into one of two buckets.

Traditional TSP

• You put in money before income tax is taken out.
• That lowers your taxable pay today.
• You pay income tax when you take the money out in retirement.

Roth TSP

• You put in money after income tax is taken out.
• You get no tax break today.
• Qualified withdrawals in retirement are tax-free, including all the growth.

That's the whole difference. Same funds, same fees, same limits. Only the timing of the tax bill changes.

Rules worth knowing

• One shared limit. For 2026, you can put in up to $24,500 across both types combined. If you're 50 or older, you can add catch-up contributions. See our guide to TSP contribution limits for 2026 for the full numbers.
• No income limit. Unlike a Roth IRA, anyone can pick Roth TSP, no matter how much they earn.
• Agency match is always traditional. Your agency's matching money goes into your traditional balance, even if you pick Roth for your own pay.
• The 5-year rule. For tax-free Roth withdrawals, you must be at least 59½ and have waited five years since January 1 of the year you made your first Roth contribution.
• No required withdrawals on Roth. Roth TSP balances are no longer subject to required minimum distributions. Traditional balances still are.

You can read the official details at TSP.gov.

Roth TSP vs Traditional TSP: How the Math Works

Here's the thing most people miss. If your tax rate stays the same, the two options end up in the same place. Really.

Let's prove it. Say you have $10,000 of pay you want to save. Your tax rate is 22% today. You expect to grow the money at 7% a year for 25 years. At that rate, money grows about 5.4 times over.

Traditional TSP:

1. The full $10,000 goes in.
2. After 25 years, it grows to about $54,270.
3. You pay 22% tax on withdrawal, about $11,940.
4. You keep about $42,330.

Roth TSP:

1. You pay 22% tax first. Only $7,800 goes in.
2. After 25 years, it grows to about $42,330.
3. You pay no tax on withdrawal.
4. You keep $42,330.

Same result. So the real question isn't "which account is better?" It's "will my tax rate be higher or lower in retirement?"

What if your tax rate changes?

Let's run the same $10,000 with a different retirement tax rate.

• Retirement rate of 12%: Traditional leaves you about $47,760. Roth leaves $42,330. Traditional wins.
• Retirement rate of 22%: Both leave about $42,330. Tie.
• Retirement rate of 24%: Traditional leaves about $41,250. Roth leaves $42,330. Roth wins.

This is why a good TSP tax strategy starts with one question: where will your tax rate be later?

Why the take-home pay feels different

Roth costs more out of your paycheck. If you put in $400 per pay period, the Traditional option takes less from your take-home pay because of the tax break. Roth takes the full $400 from after-tax pay. Keep that in mind before you switch.

Should I Choose Roth TSP? Questions to Ask Yourself

If you're asking "should I choose Roth TSP," run through these five questions.

1. Are you early in your career?

Younger employees often sit in the 10% or 12% bracket. Pay rises with each grade and step, so your tax rate will likely climb. Paying 12% now to avoid 22% later is a smart trade. A new GS-5 or GS-7 often fits here.

2. Will you have a lot of income in retirement?

Many federal retirees forget how much income they'll have. Think about these pieces:

• Your FERS pension
• Your Social Security
• Your TSP withdrawals
• Any military retirement pay

Add those up. For a long-serving employee, that can easily land in the 22% or 24% bracket, and your TSP withdrawals sit on top of everything else. Our guide on how your pension, TSP, and Social Security are taxed shows how these layers stack.

3. Are you in a high bracket now?

If you're a GS-13 or above in a high-pay area, the Traditional tax break is worth more to you. A deduction at 24% saves more than a deduction at 12%.

4. Do you want control over taxes later?

Roth money gives you a tax-free pool to draw from. That helps you manage your tax bill each year. You can pull from Roth in a high-income year and from Traditional in a low-income year. Our piece on TSP withdrawal strategies goes deeper.

5. Where will you live?

State taxes matter. If you plan to retire in a state with no income tax, your later tax rate may be lower. Check our list of best no-tax states for military and federal retirees.

Traditional TSP or Roth TSP: Real-Life Examples

Numbers help. Here are three common situations. These use rounded, simple figures to show the idea.

Example 1: The new GS-7

Maria is 26, single, and earns about $50,000. Her top tax bracket is 12%. She plans to put in 10%, or $5,000 a year.

• Traditional saves her about $600 in tax this year (12% of $5,000).
• She has 35+ years until retirement. Her pay will likely rise a lot.
• If she ends up in the 22% bracket later, Roth saves her roughly 10 cents on every dollar.

Likely fit: Mostly Roth. Her tax rate has more room to go up than down.

Example 2: The mid-career GS-13

James is 45, married, and earns $125,000. His top bracket is 24%. He expects a FERS pension, Social Security, and a big TSP.

• Traditional saves him about $1,200 in tax on every $5,000 he puts in.
• In retirement, his pension plus Social Security may fill the 12% and part of the 22% bracket.
• His TSP withdrawals could land in the 22% range.

Likely fit: Mostly Traditional, with some Roth for balance. Saving at 24% and paying at 22% or less is a good trade.

Example 3: The E-5 on deployment

Marcus is an E-5 with six years of service. He's in a combat zone, so his pay is tax-free. He's covered by the Blended Retirement System (BRS), so he gets a match.

• Roth contributions here are a strong deal. He already skipped tax on this pay, and now his growth is tax-free too.
• Traditional contributions from tax-free pay don't give a tax break, since he owed no tax to begin with.
• BRS matching goes in as traditional no matter what.

Likely fit: Roth while in the combat zone. Read more in our guide to TSP for military members and our explainer on tax-free military pay.

Want your own numbers?

These examples are a starting point. Your pay, years of service, and plans are different. The federal retirement calculator is the easiest way to get your exact numbers. It's free, and you can plug in your own situation instead of guessing.

Common Mistakes and Misconceptions

Here's where people trip up with their federal retirement savings.

"Roth is always better because taxes will go up." Maybe. Maybe not. Your personal bracket matters more than national tax policy. Retirees often drop to a lower bracket.

"Traditional is always better because I get the deduction." That's only true if your retirement rate is lower. Many high earners with big pensions find otherwise.

"I'll pick one and never look again." Your life changes. Review your choice when you get a promotion, marry, move, or change jobs.

"Roth lets me contribute extra." It doesn't. The $24,500 limit covers Roth and Traditional together.

"My match will be Roth too." It won't. Agency matching is always traditional.

"Roth withdrawals are tax-free no matter what." Not quite. You need to meet the age and 5-year rules. Pull money out too early, and part of it can be taxed.

"Roth TSP and Roth IRA are the same." They're different accounts with different rules. Roth IRAs have income limits. Roth TSP doesn't.

Step-by-Step: How to Pick Your TSP Tax Strategy

Follow these steps. They take about 30 minutes.

1. Find your tax bracket today. Check your last tax return or your pay stub. The IRS.gov site has current brackets.
2. Guess your retirement income. Add your expected FERS pension, Social Security, and military retirement pay. Use your annual retirement estimate if you have one.
3. Compare the two rates. Is your future rate higher, lower, or about the same?
4. Choose a split. Not sure? Do half and half. That's called tax diversification, and it's a perfectly good answer.
   • Higher later: lean Roth.
   • Lower later: lean Traditional.
   • Same or unsure: split it.
5. Run your numbers. Use the federal retirement calculator to see how your choice fits your whole retirement picture.
6. Make the change. Civilian employees usually change contribution types through their agency's payroll or HR system. Service members use myPay. Your TSP account at TSP.gov shows your current mix.
7. Set a reminder. Review your choice once a year, or after any big life change.

What about moving old money to Roth?

You may also be able to convert existing Traditional money to Roth inside the TSP. You'd pay tax on the converted amount, so timing matters. Our guide to TSP Roth conversions explains the new rules.

Watch for catch-up rule changes

New federal law changes how catch-up contributions work for some higher earners. Check TSP.gov for the latest details if you're 50 or older and earn a high salary.

Staying Informed

Rules change, so it helps to follow reliable news. FedWeek, GovExec, and Federal Times all cover TSP updates. For tax rules, the IRS is the final word. A tax professional can also help if your situation is complicated.

Bottom Line

Here's what to remember:

• Roth TSP means you pay tax now and take money out tax-free later.
• Traditional TSP means you get a tax break now and pay tax later.
• If your tax rate stays the same, both give you the same result.
• Early-career and lower-bracket employees often lean Roth. High earners with lower expected retirement income often lean Traditional.
• Your agency match is always Traditional, so you'll have some of both either way.
• Not sure? A mix of both is a smart, simple move.

The best choice depends on your pay, your plans, and your future income. Try the federal retirement calculator to see your personal results. Then make your pick, set a reminder, and let your savings do the work.