Starting in January 2026, you’ll be able to convert money in your traditional (pre-tax) balance to your Roth (after-tax) balance in your TSP account. This is called a “Roth in-plan conversion.” If you don’t have a Roth balance in your TSP account, your first Roth in-plan conversion will create one.

If you’re considering doing a Roth in-plan conversion, we strongly recommend that you consult a tax advisor to start planning how it would affect your taxable income and estimate how much you may need to pay in taxes.

When you convert pre-tax money from your traditional TSP balance, your Roth in-plan conversion amount will become part of your taxable income for the year. This means that you’ll pay income tax on the conversion amount based on your income tax rate. You must pay the income tax on the conversion amount using personal funds from another source, such as a savings account. You cannot use part of the conversion amount in your TSP account to pay taxes.

We’re working hard to add Roth in-plan conversions to the TSP and will share more information in the coming months. We’re also developing a calculator that will help you estimate the effects of converting traditional money to Roth money in your TSP account.

In the meantime, you can review general information about traditional and Roth on our website and in these TSP booklets:

• Summary of the Thrift Savings Plan
  
  

• Tax Rules about TSP Payments