The arithmetic
Gross per pay period equals (regular hours times regular rate) plus (overtime hours times 1.5 times regular rate). Federal FLSA requires 1.5x for hours above 40 in a workweek. California, Alaska, Nevada and Colorado add daily-overtime rules on top.
From that gross, federal income tax comes off (per your W-4 and IRS Publication 15-T). Then FICA: 6.2 percent Social Security up to the wage base, plus 1.45 percent Medicare flat. State income tax applies in 41 states plus DC. NYC, Philadelphia, Detroit and several Ohio cities tack on local tax.
Things that catch hourly workers out
Shift differentials count for overtime
If you earn a $4 night-shift differential, FLSA overtime is calculated on the differential-included regular rate, not the base. So overtime on a night shift can be 1.5 times $24 instead of 1.5 times $20.
Tipped wages have a different floor
Federal tipped minimum wage is $2.13 per hour. Your employer must top up so tips bring you to at least the regular minimum across the workweek. Several states do not allow this tip credit.
Comp time
Private-sector employers in most states cannot give time off in lieu of overtime pay. Public-sector rules differ.
Use the calculator
The PayslipIQ paycheck calculator handles hourly. Set frequency to weekly or bi-weekly, enter hours times rate as gross, pick your state. The output breaks out federal, FICA, state and net.