Should I do SDP or TSP first during a deployment?

After capturing your full BRS match, fund the SDP to $10,000 before adding extra TSP dollars. The SDP pays a guaranteed 10%, which beats the expected return of any TSP fund on a risk-adjusted basis, and the window closes when you redeploy. Then work the TSP order: Roth IRA, Roth TSP toward the elective deferral limit, and tax-exempt traditional contributions above it if you still have money left.

What happens to my Roth TSP contributions made in a combat zone?

They become the rarest money in the tax code: contributed tax-free because of the combat zone exclusion, grown tax-free inside the Roth, and withdrawn tax-free in retirement. The government never touches those dollars at any stage. That is why deployed months are the single best months of a military career to max Roth contributions.

The Deployment Money Playbook: CZTE, SDP & the Tax-Free TSP Stack

Q: How much of my pay is tax-free during a deployment?

For enlisted members and warrant officers, all military compensation is excluded from federal income tax for any calendar month with at least one qualifying day in a designated combat zone: base pay, special pays, and any reenlistment bonus signed while in the zone. Commissioned officers are capped at the senior enlisted basic pay rate plus hostile fire pay, $11,391.90 per month for 2026. FICA (Social Security and Medicare) is still withheld either way.

✓ Data checked July 7, 2026 - figures on this page verified against official sources (DFAS, IRS, DoD FMR, TSP as applicable).

Every deployment brief covers the packing list, the shots, and the family care plan. Almost none of them cover the money, and the money is not small. A combat-zone deployment switches on a stack of entitlements that, handled right, can be worth five figures immediately and six figures by retirement age. Handled wrong, most of it evaporates: the SDP never gets opened, the TSP election never changes, and the tax-free windfall becomes a lifted truck at 22% APR.

Here is the whole stack, layer by layer, with 2026 numbers. Two of these have deadlines, and the best one only works if you set it up while you are downrange. Run your own numbers in our Deployment Pay Calculator as you read.

Layer 1: The Combat Zone Tax Exclusion (the heavy hitter)

The Combat Zone Tax Exclusion (26 U.S.C. 112) is the single most valuable line in this whole playbook and the least understood. For any calendar month in which you spend even one qualifying day in a designated combat zone, your basic pay for that entire month is excluded from federal income tax. Land on the 28th and the whole month is tax free. That is the one-day rule, and it means a March-to-November deployment touches nine tax-free months even if you were only boots on ground for about eight and a half.

Enlisted members and warrant officers exclude everything with no cap. Commissioned officers are capped at the senior enlisted basic pay rate plus hostile fire pay, which is $11,391.90 per month for 2026. Below O-4, the cap almost never matters. Above it, watch your W-2.

For an E-6 over 8 pulling $4,612.80 a month in base pay, a nine-month deployment in the 22% bracket means roughly $9,100 of federal income tax that simply never gets withheld. If your state of legal residence taxes military pay, most states follow the federal exclusion too. And FICA still comes out either way. Social Security and Medicare do not care where you are standing.

The bonus timing play: a reenlistment bonus signed while you are physically in the zone is excluded from federal income tax along with everything else that month. On a $40,000 SRB at a 22% marginal rate, walking to the retention office downrange instead of at home station is worth $8,800. It is the single most valuable ten-minute appointment in this entire article. If your window and your deployment overlap, use it.

Layer 2: The LES lines to verify in your first 30 days

Three entitlements should appear on your LES shortly after you arrive. None of them are life-changing alone. All of them together, over a nine-month rotation, add up to a few thousand dollars, and finance errors on these are common enough that checking is worth ten minutes.

Hostile Fire / Imminent Danger Pay: $225 a month. IDP is location based and prorated at $7.50 per day you are actually in the designated area, so your fly-in and fly-out months usually pay less than the full $225. HFP is event based and pays the full amount for a qualifying month with no proration. You get one or the other, never both.
Family Separation Allowance: $300 a month. This is new money. The FY2026 NDAA raised FSA from $250 to $300 effective January 1, 2026, the first increase in over two decades, and it required the raise after the Pentagon sat on a discretionary authorization for two years. It kicks in after more than 30 consecutive days of qualifying separation from your dependents and prorates at about $10 a day. If you have dependents and it is not on your LES by day 45, go see finance.
Hardship Duty Pay: $50 to $150 a month depending on the location. Set by DoD per location, taxable in a normal month, excluded in a CZTE month like everything else.

Layer 3: The Savings Deposit Program (the one you must act on)

The SDP is the only guaranteed 10% return in American personal finance, and it is exclusive to deployed service members. You can deposit up to $10,000 while serving in a designated combat zone, it earns 10% annually compounded quarterly, and interest keeps accruing for up to 90 days after you return. A funded $10,000 balance on a nine-month rotation earns roughly $900, guaranteed, zero risk.

The catch is that nothing about it is automatic. Eligibility generally starts after 30 consecutive days in theater, you enroll through your finance office downrange, and deposits move by allotment, MyPay, or in person. Make it a week-one errand along with your first LES check. When you get home, withdraw it once the 90-day interest tail runs out, because the balance earns nothing after that.

Where does SDP sit in the priority order? After your BRS match, before extra TSP dollars. The match is an instant 100% return, so capture your full 5% first. After that, a guaranteed 10% beats the expected return of any TSP fund on a risk-adjusted basis, and unlike the TSP, this window slams shut when you redeploy.

Layer 4: The tax-free TSP stack (the six-figure play)

This is where a deployment stops being a nice bump and starts being a retirement event. Money you contribute to the Roth TSP from combat-zone pay is the rarest money in the tax code: it was never taxed going in, it grows tax free, and it comes out tax free in retirement. The government never touches those dollars at any point in their existence. I wrote about the Roth advantage for junior enlisted in a separate post; a combat zone takes that logic and removes the last remaining tax entirely.

The 2026 elective deferral limit is $24,500, and that is the ceiling for Roth TSP contributions. But combat-zone pay gets one more door: tax-exempt contributions to the traditional TSP do not count against the $24,500 elective deferral limit at all. They only count against the total annual additions limit, which is $72,000 for 2026. A deployed member with the cash flow can push far past the normal ceiling in a single year. One honest nuance: those tax-exempt traditional contributions come back out tax free, but the earnings on them are taxed like normal traditional TSP money. That is why Roth comes first in the order.

The contribution order, downrange:

TSP to your full 5% BRS match (free money, always first)
SDP to $10,000 (guaranteed 10%, closes when you leave)
Roth IRA to its annual limit (tax-free forever, more fund choices)
Roth TSP up to the $24,500 elective deferral limit (tax-free forever)
Tax-exempt traditional TSP above that, toward the $72,000 annual additions limit, if you still have income left

Most people never get past step 3, and that is fine. Steps 1 through 3 alone put a deployed E-5 household ahead of the vast majority of American savers that year. Project what those contributions become with the TSP Calculator.

Sanity check on the six-figure claim: a deployed E-6 who moves $23,000 of tax-free pay into Roth TSP during one rotation has, at 7% average growth over 30 years, roughly $175,000 of completely tax-free money at retirement age. One deployment, one MyPay election, six figures. That is the whole thesis of this post.

The EITC wrinkle for junior enlisted families

Combat pay excluded from your income can push a junior enlisted family's adjusted gross income low enough to qualify for the Earned Income Tax Credit, sometimes worth several thousand dollars. The IRS lets you elect to include your nontaxable combat pay in earned income for EITC purposes, and depending on your numbers, including it can make the credit bigger or smaller. Run it both ways in your tax software, or have the base tax center do it. It is a checkbox, not a project, and for an E-3 or E-4 with kids it can be the biggest single line of the whole deployment.

What not to do with it

You already know the story because every company has one: the Specialist who came home to a paid-off SDP balance, a fat tax-free savings account, and drove it straight to the dealership on Victory Boulevard. The tax code just handed you the cheapest dollars you will ever earn. Do not finance a depreciating asset with them. If a vehicle is genuinely needed, the deployment cash is a down payment on a sane used car, not the justification for a $65,000 note. The math you should be comparing is 22% APR against the tax-free Roth dollars above, and it is not close.

The pre-deployment money checklist

Confirm your location is on the current IRS combat zone list and the DoD IDP area list (designations change, and the SOUTHCOM area was not designated as of early 2026)
Submit DD Form 1561 for FSA if you have dependents
Set your TSP election in MyPay before you leave, Roth first
Build the cash-flow plan: match, SDP, Roth IRA, Roth TSP, in that order
Enroll in SDP through finance once you hit 30 days in theater
Check your LES at day 30 and day 60: IDP, FSA, HDP, tax exemption flag
If your reenlistment window overlaps the deployment, sign downrange
After redeployment: withdraw SDP after the 90-day interest tail, reset your TSP election so you do not accidentally starve your take-home pay, and rerun your withholding

The Conversation I Have Before Every Rotation

Ten years in field artillery means I have watched a lot of soldiers deploy, and the financial outcomes split cleanly into two groups that have nothing to do with rank or income. The first group spent one hour before the flight setting up MyPay, the SDP plan, and the Roth election. The second group figured they would sort it out over there, and over there has a way of eating every administrative intention you packed.

The soldiers in the first group come home to a five-figure head start that took no discipline at all downrange, because the money never hit their checking account in the first place. Automation beats willpower in a place where you cannot spend money anyway. There is no better savings environment on earth than a FOB: housing is covered, food is covered, and the nearest dealership is several thousand miles away. The system briefly makes wealth-building the default. All you have to do is not opt out.

If you have a deployment on the horizon, run the Deployment Pay Calculator tonight, then spend the hour in MyPay. Future you, sitting on tax-free Roth money at 60, will not remember the hour. He will absolutely remember the balance.

Frequently Asked Questions

How much of my pay is tax-free during a deployment?

For enlisted and warrant officers, all of it, for every calendar month with at least one qualifying day in the zone: base pay, special pays, and any bonus signed downrange. Commissioned officers are capped at $11,391.90 per month for 2026 (the senior enlisted rate plus hostile fire pay). FICA is still withheld for everyone.

SDP or TSP first?

Match first, always. Then fill the SDP, because its guaranteed 10% beats any fund's expected return and the window closes when you redeploy. After that, work the Roth order: Roth IRA, then Roth TSP toward the elective deferral limit, then tax-exempt traditional contributions above it if there is anything left.

Do I need to file anything to get the tax exclusion?

No. DoD tracks qualifying service and DFAS applies the exclusion automatically on your LES and W-2. Your job is verification, not paperwork: check that the exemption shows up on your LES in month one, and check Box 1 of your W-2 at tax time. If it looks wrong, finance can issue a corrected W-2.

Related reading: Military Tax Advantages You're Missing covers the year-round tax picture, and the Roth TSP advantage post explains why low-tax years are Roth years. Deploying is the ultimate low-tax year.