Common rates at time and a half
$15 → $22.50 · $16 → $24 · $18 → $27 · $20 → $30
$22 → $33 · $25 → $37.50 · $28 → $42 · $30 → $45
The math is just rate × 1.5, but the mental arithmetic trips people at odd rates — the shortcut is "your rate plus half your rate." $23 plus $11.50 is $34.50, done.
Where the 1.5 legally comes from
The Fair Labor Standards Act of 1938 set the overtime premium at one and one-half times the regular rate — the "half" is the employer's penalty for using more than 40 of your weekly hours, deliberately priced to make hiring another worker attractive instead. Double time is never federally required; it comes from state law (California) or contracts — the same goes for holiday pay, which no federal law mandates, so working a holiday only pays extra if your employer's policy says so.
Checking a paycheck
Count the premium hours on your stub, multiply by your rate × 1.5, and compare. If it's short, the usual culprit is the "regular rate" — differentials and bonuses belong in the base before the 1.5 is applied. Our shift differential calculator shows that blended rate.