Federal & Military Retirement Tools
Estimate the tax you would owe now, and compare the long-term after-tax value of converting traditional TSP dollars to Roth.
Conversion Worksheet
Enter the details below. The worksheet updates as you type. It uses the tax rates you provide, so it does not guess your bracket for you. If you are unsure of your marginal rate, ask your tax preparer or check last year's return.
Your inputs
Projected result
| Federal tax owed this year | $11,000 |
|---|---|
| Roth value at withdrawal (tax-free) | $119,828 |
| Traditional value after tax | $91,069 |
| Projected difference | +$28,759 |
What this suggests
Converting is projected to leave you with about $28,759 more at withdrawal, because you expect a higher tax rate in retirement than you pay today.
Break-even retirement tax rate: 22%. If you expect to be taxed above this rate when you withdraw, converting tends to win. Below it, staying traditional tends to win.
Estimates only. Figures are rounded and assume a steady growth rate. This tool does not account for state taxes, the five-year rule, RMD timing, or the effect of a conversion pushing you into a higher bracket. See the notes and disclaimer below.
Background
A Roth in-plan conversion lets you move money from your traditional, pre-tax TSP balance into your Roth, after-tax balance, all inside your Thrift Savings Plan account. You do not withdraw the money or open a separate account. You simply change how it will be taxed later.
The trade is straightforward. You pay ordinary income tax now on the amount you convert, because those dollars have never been taxed. In exchange, that money and all of its future growth can come out tax-free in retirement, provided you meet the holding rules.
This matters for federal employees and military members because the option is new. Starting in 2026, TSP participants can convert traditional balances to Roth directly inside the plan for the first time. Before that, the only way to get TSP money into a Roth was to roll it out to an outside Roth IRA. Because the in-plan feature is so recent, clear guidance built specifically for TSP participants is still thin, which is exactly why this page exists.
Method
The worksheet compares two futures for the same block of pre-tax money: converting it to Roth today, or leaving it in the traditional balance and paying tax when you withdraw.
If you pay the tax from outside savings, the full amount you convert stays invested and grows tax-free, so its value at withdrawal is the amount multiplied by your growth over the years you selected. If you instead pay the tax out of the conversion itself, only the after-tax portion lands in the Roth balance and grows.
The same starting amount grows at the same rate, but you owe ordinary income tax when you withdraw. The worksheet applies your expected retirement rate to the ending balance to show what you would actually keep.
The single biggest factor is whether your tax rate in retirement is higher or lower than it is today. If you expect to pay a higher rate later, paying the tax now at a lower rate tends to win. If you expect a lower rate later, waiting tends to win. Paying the conversion tax from outside savings shifts the math further in favor of converting, because more money stays sheltered.
Illustration
Suppose a federal employee converts $50,000 of traditional TSP money. She pays a 22% marginal rate today, expects a 24% rate in retirement, plans to leave the money invested for 15 years, and assumes 6% average annual growth. She pays the conversion tax from savings outside the account.
| Amount converted | $50,000 |
| Federal tax owed this year (22%) | $11,000 |
| Growth over 15 years at 6% | × 2.397 |
| Roth value at withdrawal, tax-free | $119,828 |
| Traditional value after 24% tax | $91,069 |
| Projected advantage of converting | $28,759 |
Because she expects a higher rate in retirement than she pays today, and pays the tax from outside savings, the conversion comes out ahead in this example. Change any input in the worksheet above and the result changes with it.
Common Questions
Thrift Savings Plan participants, which includes most federal civilian employees and members of the uniformed services. The in-plan conversion feature became available inside the TSP in 2026. Confirm your specific eligibility and the current process on the official TSP website before acting.
It can. The amount you convert is added to your taxable income for the year, so a large conversion can move part of your income into a higher bracket. Many people spread conversions across several years to stay within a target bracket. This calculator uses a single flat rate you enter, so if you expect part of a conversion to be taxed at a higher rate, run the numbers using a blended estimate or split the amount.
Paying from savings outside the account is generally the stronger move, because it lets the full converted amount keep growing tax-free. It may also be the required method for an in-plan conversion. Use the toggle in the worksheet to see the difference between the two.
Roth conversions carry holding requirements before earnings can be withdrawn tax-free and penalty-free. Withdrawing converted money too soon can trigger taxes or penalties. The rules have age and timing details this calculator does not model, so treat the projection as a long-term comparison and confirm the withdrawal rules for your situation.
No. It estimates federal income tax only, using the rates you enter. State income tax, if it applies where you live, would increase the tax owed on the conversion. Add your state's effect separately when you plan.
No. This is an educational estimate to help you understand the trade-offs. A conversion has lasting tax consequences, so talk with a qualified tax professional or financial planner before you convert.
References
Rules and figures change. Verify current details with the official sources above before making a decision.
Please Read
This calculator is provided for general educational purposes only and does not constitute tax, legal, investment, or financial advice. It produces simplified estimates based on the figures you enter and a set of assumptions described on this page.
It does not account for state taxes, the five-year holding rule, required minimum distribution timing, changes in tax law, Medicare premium effects, or the possibility that a conversion pushes you into a higher bracket. Actual results will differ. Investment growth is not guaranteed and past performance does not predict future returns.
Before making any Roth conversion decision, consult a qualified tax professional or financial planner and confirm current rules with the official Thrift Savings Plan and Internal Revenue Service resources listed above.