To change your TSP contributions in MyPay, sign in at mypay.dfas.mil, open the Thrift Savings Plan option, and enter a new percentage for each pay category. One detail catches people every time: you have to re-enter percentages for every pay category, not just the one you’re adjusting. Blank fields can be treated as zero, which can wipe out contributions you meant to leave alone. The change takes effect no later than the first full pay period after your agency receives it.
Who Uses MyPay for This
MyPay is the Defense Finance and Accounting Service payroll portal. Active-duty service members, reservists, and DFAS-serviced DoD civilians manage their TSP contribution elections there.1Defense Finance and Accounting Service. Thrift Savings Plan (TSP) for Active Duty USA, USN, USAF and SF Members Members without MyPay access can submit a TSP-U-1 election form through their finance office.2Defense Finance and Accounting Service. TSP for Reserve/Guard – Section: Starting Your TSP Contributions
Federal civilian employees outside DoD generally don’t use MyPay for TSP. Many agencies run their own payroll self-service systems, and some DoD civilians use the GRB Platform instead.3Defense Finance and Accounting Service. Thrift Savings Plan (TSP) If you’re a civilian and unsure which system applies to you, check with your agency’s human resources or payroll office.
Logging In
Go to mypay.dfas.mil and sign in with your Login ID and password. If you’ve never set up an account, click “Forgot or Need a Password” to have a temporary password mailed to your address on file, then return to create your profile.4Defense Finance and Accounting Service. Using myPay Once you’re in, look for the menu option labeled Thrift Savings Plan under your pay management options. Clicking it opens the screen where you set contribution percentages.
Entering Your New Percentages
The contribution screen has fields for each pay category: basic pay, special pay, incentive pay, and, for military members, bonus pay. Each category has separate fields for Traditional and Roth contributions. You enter a percentage in every field that should carry a deduction.
Here is the part that trips people up. If you fill in only the category you’re changing and leave the others blank, MyPay may treat those blanks as zero and stop contributions from those pay types.5Defense Finance and Accounting Service. Thrift Savings Plan (TSP) for Active Duty USA, USN, USAF and SF Members – Section: Changing TSP Elections Say you currently contribute 10% of basic pay and 5% of incentive pay, and you want to raise basic pay to 15%. Enter 15% for basic pay and re-enter 5% for incentive pay. Leaving incentive pay blank could end that deduction entirely.
You can contribute from 1% to 100% of special pay, incentive pay, or bonus pay, as long as you’re contributing at least 1% from basic pay.6The Thrift Savings Plan (TSP). Contribution Types
Splitting Traditional and Roth
Traditional contributions come out pre-tax, so your current paycheck is slightly larger, and you pay tax on the money when you withdraw it later. Roth contributions are taxed upfront, but qualified withdrawals in retirement come out tax-free, including the investment earnings.7The Thrift Savings Plan (TSP). Traditional and Roth TSP Contributions You can split any way you want. Someone contributing 10% of basic pay might put 6% into Traditional and 4% into Roth. The combined total counts toward the annual IRS limit.
Reviewing and Submitting
After you enter your percentages, MyPay shows a review screen with everything you just typed: each pay category and each Traditional or Roth split. Check every field. This screen is your last chance to catch a typo before the change processes.
Click Submit to finalize. MyPay generates a confirmation screen with the details of your change. Take a screenshot or print that page. The change isn’t official until you complete this step, and having a record protects you if something goes wrong in processing.
Verifying It Actually Happened
The confirmation screen tells you what you requested. Your Leave and Earnings Statement tells you what actually happened. After the change should have taken effect, pull up your next LES. The TSP section breaks out Traditional and Roth contributions separately. Compare those against what you submitted.8Defense.gov. Your Leave and Earnings Statement You can also log into your account at tsp.gov to confirm the posted contributions match. If something doesn’t line up, contact your finance office right away.
When the Change Takes Effect
A contribution change goes into effect no later than the first full pay period after your employing agency receives the election.9GovInfo. 5 CFR Part 1600 Subpart C – Section: 1600.12 Contribution Elections Submit on a Tuesday and you probably won’t see the change in that week’s pay. It typically shows up in the next full pay period. TSP contributions are tracked by pay date, not the date the money lands in your TSP account, so the pay date determines which calendar year the contribution counts toward for IRS limit purposes.10The Thrift Savings Plan (TSP). 2026 TSP Contribution Limits
There’s no cap on how often you can change your election. Every pay period, if you want.
This Doesn’t Change How Your Money Is Invested
Changing your contribution amount is a different action from changing how your money is invested. A contribution election controls how much comes out of your paycheck and whether it goes to your Traditional or Roth balance. An investment election controls which TSP funds your new deposits go into, such as the C Fund, S Fund, or a Lifecycle fund.11eCFR. Part 1600 Employee Contribution Elections, Investment Elections, and Automatic Enrollment Program The contribution percentage is set through MyPay. Investment elections are made through your TSP account at tsp.gov. Changing one does not change the other.
Before You Pick a Percentage, Check Two Things
The Annual Limit
The IRS elective deferral limit for TSP in 2026 is $24,500. That’s the combined cap on your Traditional and Roth employee contributions for the year.12Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 Catch-up contributions are available on top of the limit if you turn 50 or older during the year. Once your regular contributions hit the elective deferral limit, additional contributions automatically count toward the catch-up limit; no separate election needed.13The Thrift Savings Plan (TSP). Contribution Limits
The FERS Front-Loading Trap
If you’re covered by the Federal Employees Retirement System, this matters. Every FERS participant gets an automatic agency contribution of 1% of basic pay whether or not they contribute anything. On top of that, the agency matches contributions on the first 5% of basic pay: dollar for dollar on the first 3%, and 50 cents on the dollar on the next 2%. Contribute 5%, and the agency puts in a total of 5% (1% automatic plus 4% matching).6The Thrift Savings Plan (TSP). Contribution Types
Here’s where FERS employees lose money. If you set your percentage high enough to hit the $24,500 limit before the year’s final pay period, your contributions stop for the rest of the year. So do the agency matching contributions. The automatic 1% keeps flowing, but the match disappears, and once it’s gone you can’t get it back. Pace your contributions so at least 5% of basic pay is still going in through the last pay period of the year. The calculator at tsp.gov can help you find the right percentage. If you’re contributing more than roughly 8 to 10% of pay, run the numbers before submitting.