The state where your 401(k) is not a tax break
Pennsylvania's 3.07% flat rate looks like the friendliest tax in the region - until you learn its famous exception: traditional 401(k) contributions are NOT deductible for PA purposes. Unlike federal law and nearly every other state, Pennsylvania taxes your retirement deferrals in the year you earn them (in exchange, qualified withdrawals in retirement come out state-tax-free). This calculator handles that correctly - toggle the 401(k) field and watch the PA line stay put while the federal line drops.
The other Pennsylvania signature is local: nearly every municipality levies an earned income tax, commonly about 1%, and Philadelphia's wage tax runs several times higher - enter your local rate above. Add the flat $52 Local Services Tax and the tiny 0.07% unemployment contribution, and the "simple" 3.07% state turns out to carry the busiest small print in the region.