Software developer here. I've spent the past few months deep in FLSA payroll regulations (I build software in this space), and this is the thing I most wish every nurse knew: Night and weekend differentials aren't just extra pay for those hours — they're legally required to raise the rate your overtime is calculated from. The rule: overtime is 1.5× your "regular rate," and the regular rate is NOT your base rate. It's (all straight-time pay including differentials) ÷ (hours worked). 29 CFR § 778.207(b) says shift differentials must be included. No exceptions for hospitals. What that looks like in real numbers — $45 base, $4.50 night diff, 44-hour week: - Straight time: 44 × $45.00 = $1,980 - Night diff: 44 × $4.50 = $198 - Regular rate: $2,178 ÷ 44 = $49.50 (not $45!) - OT premium owed: 4 × ½ × $49.50 = $99.00 - What many payroll systems pay: 4 × ½ × $45.00 = $90.00 That's $9 short in one week. Small enough that nobody notices, big enough to matter over a year of regular OT — and it scales with your diff. Nurses with $7–10/h night diff are losing a lot more. How to check your own stub: 1. Add up everything you earned at straight time, including every differential (before any OT line). 2. Divide by total hours worked. That's your regular rate. 3. Your OT line should work out to at least an extra ½ × that rate for every OT hour — not ½ × base. If it doesn't: payroll first (bring the math), then your union if you have one, then the Department of Labor's Wage and Hour Division. In general, FLSA back-wage recovery has a 2-year statute of limitations, or 3 years for willful violations. Note for CA folks: daily OT / double time stack on top of this, but the regular-rate rule applies there too. Hospitals on the 8/80 system: same math, different OT trigger. Curious what this community sees: does your hospital include diffs in the OT rate? And what do night/weekend diffs look like where you are — flat $/h or % of base?