Run the same salary through three different paycheck calculators and you'll get three different answers. None of them explain why. That bothered me enough to spend three weeks building an alternative. The result is payculate.org — a paycheck calculator for all 50 US states and DC where every deduction line opens up and shows its own arithmetic . The interesting problem wasn't the code The tax math itself is straightforward: progressive brackets are a loop, FICA is two multi...