This is easy to calculate because the tax savings work the same way as they do for 401ks. Just plug your household income infor to smart asset and compare the taxes paid before/after increasing tsp contributions.

I swear there used to be a calculator online that showed how much my taxes would be reduced if I increased my tsp. Does that still exist somehow? I can't find it. I've recently gotten a promotion and trying to determine how much increasing my tsp will reduce my tax obligations.