Traditional vs Roth TSP is a tax-timing choice, not a choice between two investment menus. Traditional contributions are taken from pay before income tax. Roth contributions are taxed in the year you earn them. The TSP funds can be the same either way. What changes is when the IRS counts the money, and whether later earnings can come out tax-free. Fund selection is a separate decision, covered on Hoxton’s page about retirement asset allocation in Martinsburg.
Call (304) 876-2619 to talk through a TSP tax election.
Call (304) 876-2619 to review your TSP tax election
What Is the Difference Between Traditional and Roth TSP?
The Thrift Savings Plan lets you decide when your own contributions are taxed. Designate the contribution as Roth if you want it counted as income in the year you earn it. Designate it as traditional if you want it counted when you withdraw it. You can also do some of each.
That split lives inside one TSP account. Your fund choices, including the G, F, C, S, I, and Lifecycle funds, are separate from the tax label on each dollar. The same fund can hold both kinds of money. The two contributions can still be taxed differently later.
The TSP’s traditional and Roth contributions page is the source for that rule. It is also the place that now explains Roth in-plan conversions, which became available in January 2026. A conversion moves money that is already in the traditional balance into the Roth balance. It is not the same decision as the election you make on each paycheck.
How Are Traditional TSP Contributions Taxed?
With a traditional election, the contribution leaves your pay before income-tax withholding. The TSP says this can lower your current taxable income. The tradeoff shows up later. A withdrawal from the traditional balance is taxed as income. That tax covers both the contributions and the earnings, at the rates in effect that year.
That later tax is ordinary income, not a special TSP rate. A large withdrawal in a year when you also start a FERS annuity or claim Social Security can stack on top of other income. Hoxton’s guide to how federal retirement benefits are taxed walks through those separate income streams. This article stays on the contribution label.
- The paycheck deduction reduces taxable wages in the year of the contribution.
- Growth inside the traditional balance is tax-deferred, not tax-free.
- Withdrawals of contributions and earnings are taxed as income in the year you take them.
- The rate you pay later depends on that year’s income, filing status, and tax law, not on the rate you avoided today.
A lower tax bill this year is useful only if the dollars you keep are put to work. Spending the tax savings, or stopping contributions once the refund looks smaller, gives up the point of the deferral.
When Are Roth TSP Withdrawals Tax-Free?
Roth TSP contributions are part of your taxable pay in the year you make them. Ordinary withholding still applies. You do not pay tax again on the portion of a withdrawal that is your own Roth contributions. Earnings can also come out tax-free, but only when those earnings are qualified.
Earnings are qualified only when both of these are true.
- Five years have passed since January 1 of the calendar year of your first Roth TSP contribution.
- You are at least age 59½, permanently disabled, or deceased.
Miss either test and the earnings portion can be taxable. The contributions themselves are still recovered without an extra tax. That is why the five-year clock is worth starting even with a small Roth election, if Roth contributions otherwise fit. The clock is measured from January 1 of the first Roth TSP year, not from the date of each later contribution.
The IRS Roth comparison chart uses the same qualified-distribution idea for designated Roth accounts: the five-year holding period plus age 59½, disability, or death. A Roth TSP is a designated Roth account inside an employer plan. It is not a Roth IRA, and the chart’s Roth IRA income limits do not apply to TSP participation.
Can You Contribute to Both Traditional and Roth TSP?
Yes. The TSP election form has a line for traditional contributions and a separate line for Roth contributions. You can enter a percentage or a whole-dollar amount on each line. A blank line means zero for that type. You do not need two accounts. You also do not have to pick one label for your whole career.
The combined traditional and Roth employee contributions share one elective deferral limit. For 2026, the TSP bulletin setting that year’s limits puts the elective deferral limit at $24,500, up from $23,500 in 2025. Agency automatic and matching contributions do not count toward that employee limit. Catch-up contributions for participants who are old enough are also outside it.
A split can be as simple as sending the first dollars to traditional and a smaller slice to Roth, or the reverse. The right mix is a tax question, not a fund question. People who expect a higher tax rate in retirement often look harder at Roth. People in a peak earning year often look harder at traditional. Neither rule is automatic, because FERS, Social Security, a spouse’s income, and the state you live in can all move the rate.
Payroll is where the election actually happens. Civilian employees typically use their agency system, such as Employee Express, GRB, LiteBlue, myPay, or NFC EPP. Uniformed service members generally use myPay or Direct Access. Paper Form TSP-1 goes back to the agency or service, not to the TSP.
How Do the 2026 Limits Apply to Both Elections?
The employee limit is shared. You cannot put $24,500 in traditional and another $24,500 in Roth in the same year. Once employee contributions hit the elective deferral limit, the TSP stops accepting more for someone who is not eligible for catch-up contributions. Hitting that limit before the last pay date can also stop matching for the rest of the year. That applies to FERS and eligible BRS participants, because the match is calculated on each pay period’s contribution.
| Tax question | Traditional TSP | Roth TSP |
|---|---|---|
| When is the contribution taxed? | Later, when you withdraw it. | In the year you contribute. |
| Are your own contributions taxed again? | Yes. They are taxed with the earnings. | No. They are not taxed again. |
| How are earnings treated? | They are tax-deferred, then taxed. | They are tax-free only if qualified. |
| What is the 2026 employee cap? | It shares the $24,500 combined cap. | It shares the same $24,500 cap. |
| Does the agency match change? | No. The match follows the contribution. | No. The tax label does not change it. |
Those 2026 figures come from the TSP bulletin on 2026 contribution limits. The regular catch-up limit is $8,000. That amount is for ages 50 to 59, and for age 64 and over. Participants ages 60 through 63 have a catch-up limit of $11,250. Catch-up rules, including the Roth catch-up rule for higher earners, deserve their own review. They are not a reason to skip the basic tax choice on contributions under the elective deferral limit.
A separate article will cover the contribution-limit tables in full. Use the figures here only to see that traditional and Roth share one employee cap.
Does the Agency Match Depend on Roth or Traditional?
For FERS employees and eligible Blended Retirement System members, the match is based on basic pay you contribute each pay period, up to 5 percent. The TSP’s contribution-types page states the formula. The first 3 percent of pay is matched dollar for dollar. The next 2 percent is matched at 50 cents on the dollar. Add the automatic 1 percent, and a 5 percent contribution draws agency money equal to 5 percent of basic pay.
That formula does not ask whether your 5 percent was traditional, Roth, or a mix. Stopping your own contributions stops the match. The automatic 1 percent continues. Reaching the elective deferral limit early can also shut off the match for later pay periods, which is a scheduling problem, not a Roth-versus-traditional problem.
Automatic enrollment puts many newer hires into the traditional balance. For many people hired or rehired on or after October 1, 2020, the default is 5 percent of basic pay. That default stays in place unless you change the election. A new employee who wants Roth dollars has to make that change. Leaving the default in place is itself a traditional election.
CSRS participants and others who do not receive agency contributions still choose traditional, Roth, or both for their own deferrals. The absence of a match does not remove the tax-timing choice.
Which Choice Fits a Federal Paycheck?
There is no TSP rule that says one election is better. Compare the tax rate on the contribution with the rate you expect on the withdrawal. Include income you cannot turn off, such as a pension.
Traditional contributions are often considered when this year’s rate is the high point. A promotion year, a spouse’s peak earnings, or a year with little room left in a lower bracket can make the current deduction valuable. The risk is a larger traditional balance later, when required withdrawals and a pension arrive together.
Roth contributions are often considered when today’s rate looks modest next to later income. They also fit if you want retirement money that does not add to taxable income. Qualified Roth earnings are not taxed on the way out. That can matter if a pension plus Social Security already fills the lower brackets.
A split is a practical third path. Many federal employees contribute at least 5 percent so they do not leave the match behind. They then decide how much of that 5 percent, and of any amount above it, should be Roth. Hoxton’s overview of federal employee retirement benefits shows where the TSP sits next to the annuity and insurance. The election in this article is narrower: the tax label on your own deposits.
Two boundaries are worth keeping:
- Do not treat a Roth TSP like a Roth IRA. Employer-plan rules, including the qualified-distribution tests above, are the ones that apply. IRA income limits are a different system.
- Do not treat an in-plan conversion as a substitute for the payroll election. Converting traditional money later adds that amount to the year’s taxable income. The TSP says the tax must be paid from money outside the TSP.
What Should You Decide Before Changing the Election?
Read your latest pay statement before you submit a new election. A mid-year switch does not rewrite contributions already posted. Work through the election in this order:
- Note the current traditional amount and the current Roth amount on your pay statement.
- Check whether you are on pace to hit the elective deferral limit before the last pay date.
- Decide how much of the next contribution should be traditional and how much should be Roth.
- Submit the change in your agency or service payroll system, not to the TSP.
Then line the TSP up with income you do not control as easily. A FERS annuity, Social Security, and taxable interest can fill a bracket before any TSP withdrawal. If those sources already use the lower brackets, adding more traditional TSP may raise the rate on later withdrawals. If those sources are small, the traditional deduction may still be the better use of this year’s rate.
Hoxton’s page on federal employee retirement tax withholding covers how tax is taken out of benefit payments. Withholding is not the same as the contribution election, but both affect the refund or the balance due. Tax-efficient retirement withdrawals picks up the question of which account to spend first after you stop working. Roth conversion strategy for retirees covers conversions after the working years. None of those pages chooses the traditional or Roth box on your current payroll form.
If you are comparing whether the TSP is still the right home for the money after you separate, that is a different decision. Should you keep money in the TSP after retirement addresses the account itself. The tax label you chose while working still matters after you leave. Traditional and Roth balances do not become the same kind of money on your last day.
Ask Hoxton to review your TSP election alongside the rest of your retirement income.
Call (304) 876-2619 before you change your TSP election
Frequently Asked Questions
Is Roth TSP better than traditional TSP?
Neither is better for every employee. Traditional contributions reduce taxable income now and are taxed later. Roth contributions are taxed now, and qualified earnings can come out tax-free. The better fit depends on your current rate, your expected future rate, and the other income you will have.
Do traditional and Roth TSP share the same contribution limit?
Yes. Employee traditional and Roth contributions are added together under the elective deferral limit. For 2026 that limit is $24,500. Agency contributions do not count toward it. Catch-up contributions, for people who qualify, are on top of it.
Are Roth TSP earnings always tax-free?
No. Your own Roth contributions are not taxed again when withdrawn. Earnings are tax-free only when they are qualified. That takes five years from January 1 of your first Roth TSP year. You must also be at least 59½, permanently disabled, or deceased. If a withdrawal fails that test, the earnings can be taxable.
Will I still get the agency match if I choose Roth?
FERS and eligible BRS matching is based on the percentage of basic pay you contribute each pay period, up to 5 percent. The formula does not change because you labeled the contribution Roth. You still need to contribute each pay period to keep receiving the match.
Can I switch from traditional to Roth later?
You can change future contributions through your agency or service payroll system. Contributions already in the traditional balance stay traditional unless you convert them. A Roth in-plan conversion has been available since January 2026. The converted amount is taxable that year. The tax has to be paid with money from outside the TSP.
This article contains general information that is not suitable for everyone and was prepared for informational purposes only. Nothing contained herein should be construed as a solicitation to sell or buy any security or as an offer to provide investment advice. Hoxton Planning & Management LLC is a registered investment adviser. For additional information about Hoxton Planning & Management LLC, including its services and fees. Send for the firm’s disclosure brochure using the contact information contained herein or visit advisorinfo.sec.gov. All investing involves risk, including the possible loss of principal. Past performance is not indicative of future results, and no investment strategy can guarantee profit or protect against loss in periods of declining markets. Tax laws are complex and subject to change. The tax information provided is general in nature and should not be construed as tax advice. Consult a qualified tax professional regarding your specific circumstances before making any tax-related decisions.