Military Mega Backdoor Roth: Max TSP Contributions in a Combat Zone 2026

In 2026, you can contribute up to $72,000 to your Thrift Savings Plan if you serve in a combat zone tax exclusion (CZTE) area.

Combined with the new in-plan Roth conversions, deployed military members can execute a ‘Military Mega-Backdoor Roth' to shelter up to $87,000 tax-free.

Military pay received in a CZTE is federal and state income tax-free, an unlimited benefit for enlisted and up to about $10,295 per month for officers.

CZTE pay unlocks the triple tax benefit of a military deployment, where you contribute tax-free income, the money grows tax-free, and you can withdraw it tax-free after age 59.5.

TSP limits are set annually by the IRS and are available on the contributions limit page here. Here is the official IRS list of CZTE areas.

Maximize Annual Additions Limit TSP CZTE Game Plan

Here is the gameplan to maximize your TSP CZTE contributions:

1. Set your Roth TSP contributions so you max the elective deferral limit by the end of the year. This is $24,500 in 2026. For example, if you earn $100,000 in base pay, set 24% so you contribution $24,000 by years end
   
2. Set your Traditional TSP contributions so you get to the annual additions limit minus your 5% match, minus the elective deferral limit, by the end of the year. For example, in 2026 it's $72,000 minus $24,500 minus your 5% match.

$72,000 - $24,500 - (5% x $100,000 = $5,000) = $42,500
$42,500 / $100,000 = 42% Traditional TSP contribution

3. Convert your Traditional TSP contributions to Roth TSP every month using an in-plan TSP Roth Conversion. This avoids large buildups of capital gains, which will not convert tax-exempt.

4. Contribute the maximum to your Roth IRA and your spouse's Roth IRA if you're lucky to have a spouse.

Military Mega-Backdoor Roth TSP Calculator

Things to Watch Out For or “Gotchas”

1. You can not exceed $24,500 in contributions to the Roth TSP at any time during the calendar year. 
2. When you return home, any further contributions for the rest of the year are subject to the elective deferral limits ($24,500 in 2026) 
3. If your traditional TSP account has already exceeded $24,500 in contributions during the calendar year, you can’t contribute more taxable pay to it.
4. You cannot set your TSP to 100% in MyPay. TSP contributions are capped to 92% to leave enough space for the 7.5% payroll tax (rounded up to 8%). This covers your Medicare and Social Security FICA taxes. If you try to contribute more than 92%, DFAS will reject the transaction and contribute 0% for the month.
5. If you hit the annual additions limit or elective deferral limit before December, you lose out on the 5% match in December.

Elective Deferral Limit vs Annual Additions Limit TSP

From the TSP.gov page on limits:

Elective deferral limit: This limit applies to the combined total of traditional and Roth contributions. For uniformed services members, this does not apply to traditional contributions from combat-zone pay.

Annual additions limit: The annual additions limit is the total amount of all the contributions you make in a calendar year. This limit is per employer and includes money from all sources: employee contributions (tax-deferred, after-tax, and tax-exempt), Agency/Service Automatic (1%) Contributions, and Agency/Service Matching Contributions. It does not include catch-up contributions. The annual additions limit affects mostly members of the uniformed services who can exceed the annual elective deferral limit. The excess contributions go into the traditional portion of your account from tax-exempt pay earned in a combat zone.

Military Mega-Backdoor Roth: Convert Traditional to Roth in a CZTE

The other advantage military members have is to convert Traditional TSP contributions to their Roth TSP account. This is known as a Roth in-plan conversion. This is done on a “pro rata” basis, meaning that you can't just convert the tax-free contributions.

For example, if you have $100,000 in your Traditional TSP account, and $50,000 of it is designated tax-exempt, if you convert $50,000 to Roth, then $25,000 will convert tax-free and $25,000 will be taxable and added to your taxable income for that year.

If you converted the entire $100,000 (except for $500, which is required to remain in your Traditional TSP account), $50,000 would be tax exempt and $50,000 would be considered a taxable conversion.

Anyone in the Blended Retirement System (BRS) has money in the Traditional TSP since the 1% automatic agency contribution and 4% matching contributions go into the Traditional TSP.

Where this opportunity gets very interesting is CZTE or Combat Zone Tax Exclusion areas.

Here are a few examples of a 12 month and 6 month deployment using the 2026 numbers.

12 month deployment = $87,000 of Tax-Free Money

Let's say a servicemember is in a CZTE January to December and earns $100,000 in base pay, or $8,333 per month. This would be about a 22 year E-9 or 8 year O-3.

$100k per year is below the CZTE income limit of the highest ranking enlisted position, so it's all federal income tax-free.

The TSP contribution limits are $24,500 for 2026 elective deferral and $72,000 annual additions limit.

You can go up to the annual additions limit with Traditional TSP contributions that are tax-exempt, aka contributions made to the Traditional TSP while you are CZTE eligible.

Here's the setup:

• 24% contributions to your Roth TSP
• 43% contributions to your Traditional TSP + 5% from automatic matching = 48% total Traditional contribution
• $15,000 into you and your spouses Roth IRA ($7,500 each)

Every month, you convert the tax-exempt Traditional TSP contribution to your Roth TSP. The money is converted “pro-rata,” meaning that if there is $10,000 in the account and $5,000 is tax-exempt, and $5,000 taxable, when you move $1,000 over it's a 50/50 split between tax-exempt and taxable. In other words, you can't just move the tax-exempt portion.

By the end of the year, you've paid $0 in federal income taxes on your $100,000 of base pay. You've managed to build:

• $72,000 in to your Roth TSP (the $24k of contribution and the $48k of tax-exempt conversions)
• $15,000 of Roth IRA contributions
• $87,000 of Roth contributions in a single year for a married filing jointly O-3

Oh, and you're probably receiving BAH, BAS, etc as well.

Let that $87,000 grow for 30 years at 10%: $1.5 million

Pull 4% a year off of that = $60,000 per year for life. Tax-free.

6 Month Deployment = $74k tax-free

Let's say you only deploy to CZTE for 6 months of the year, January to June.

You can still get a good chunk of money into your Roth TSP and Roth IRA:

• 24% contributions to your Roth TSP throughout the year to hit elective deferral limit
• 70% total contributions to your Traditional TSP while in CZTE (turn off before you get back in June/July) 65% of your contribution + 5% automatic agency match
• $15,000 into you and your spouses Roth IRA ($7,500 each)

End of the year:

• + $24,000 into Roth TSP
• + $35,000 tax-exempt contributions into Traditional TSP, convert monthly to Roth TSP
• = $59,000 total into TSP, well below $72k limit
• + $15,000 into Roth IRA

= $74,000 into Roth accounts for a 6 month deployment, grows to $1.3mm over 30 years at 10%.

Taxable income for the year is $50,000 minus MFJ standard deduction of 32,200 = $17,800 you're in the 10% bracket. You'll probably get a savers credit too.

Less than $1,780 of income taxes on $100,000 of income. 1.78% effective tax rate. And that's not even including BAH, BAS, COLA.

Military pay is very low taxed.

Bonus Info

If you know the year before you are deploying, you could make Traditional IRA and Traditional TSP contributions, take the tax deduction in that prior year at 12%, and then convert them during your CZTE year at a very low tax rate, say you pay 10% or lower.

You can make 26 conversions per year, so you probably want to do a conversion every month to clear money out of the Traditional TSP so there is no growth balance that you'll have to pay taxes on.

But even if you wait until December to just make the conversion once, let's say the market rips and is up 30% for the year, you'll have to pay a bit of taxes on $14,000 of growth. (0.3 x $48,000. And the $48k wasn't all in there at the start of the year, so not much to worry about).

You'll also need to leave $500 behind in the Traditional TSP account, because of the conversion rules.

Why Would Anyone Want to Super-Max their CZTE TSP Contributions?

Why would anyone go through the hassle and deprivation of setting aside tens of thousands of dollars for retirement?

Military deployments can be one of the most financially beneficial times in your life. With low expenses (usually housing, food, and all other necessities are paid for), high income (extra deployment bonuses and tax-free pay), you have the opportunity to really accelerate your financial goals.

By contributing to your Traditional and Roth TSP up to the annual additions limit, you can lock away tens of thousands of dollars at a very low tax rate, that will grow in the low-cost, automated, diversified, and simple TSP Lifecycle Funds for decades. A single deployment can set you up for a million dollar retirement.

Additional Reading

• Max your TSP contributions and get full BRS match
• TSP Roth In-Plan Conversions, new for 2026
• Convert Traditional IRA to Roth IRA while in a CZTE to minimize taxes
• My Book: The Military Money Manual: A Practical Guide to Financial Freedom
• Savings Deposit Program: SDP Guaranteed 10% Risk-free Investment up to $10,000