Where your paycheck actually goes
Gross pay is what you negotiate; take-home pay is what you can spend. Between them sit federal income tax (charged in marginal brackets, so a raise is never fully taxed at the top rate), Social Security and Medicare (FICA), state income tax where you live, and any pre-tax deductions like a 401(k) or health premium. The take-home pay calculator walks each of those out so the number on your budget is the real one.
Hours, overtime, and comparing offers
If you're paid by the hour, two questions come up constantly: how much did I actually work, and what's an offer really worth? The time card calculator totals a week of shifts with breaks and overtime, the overtime calculator shows what those extra hours pay at time-and-a-half, and the hourly-to-salary calculator converts a wage to a yearly figure so you can line up an hourly job against a salaried one.