From January to June 2025, I contributed 7% of my income to Roth TSP and 4% to Traditional TSP. For July 2025, I switched to 11% Roth. How to adjust my withholding?

[simoneporter]

I am contributing more to Roth TSP than I was in the beginning of the year, starting in July 2025. How to I adjust my withholding so I do not owe a large tax bill next year?

[Opus 17]

You should not have to, the withholding should be self-adjusting.  When you switched from pre-tax to after-tax contributions, your taxable pay increased and your withholding should automatically increase as well.