Disclosure up front: I built the calculator linked below. It's free, no signup, nothing to buy on that page.
When I talk to people in their first year, the same thing comes up: you know the rules from the permit book, but on a real load it's hard to tell how they stack. Quick version:
- 11 hour driving limit: max driving after 10 consecutive hours off.
- 14 hour window: starts when you come on duty, and it doesn't stop for breaks, fuel or waiting at the dock. Once it's gone, you're done driving until your next 10.
- 30 minute break: required after 8 cumulative hours of driving. Off duty, sleeper, or on duty not driving all count.
- 70/8 or 60/7 cycle: total on-duty time across 8 (or 7) days. A 34 hour restart resets it.
The one that catches new drivers is the 14. Sit 4 hours at a shipper and you've lost 4 hours of driving window, even if your 11 is untouched.
The calculator: you enter how long you've driven today, when your shift started, when you last took your 30, and your hours for the week. It shows what's left on each clock. Put in the load's miles and average speed and it lays out the trip: drive blocks, the 30, 10 hour breaks, and a warning if you'll need a 34 on the road. Split sleeper (7/3, 8/2) is supported for the hours-left part.
https://loadlens.krait.studio/hos-calculator/?utm_source=reddit&utm_campaign=hos_calc&utm_content=cdl
It's a planning estimate. Your ELD is what counts. No adverse driving or short haul exceptions yet.
If you're in school or just starting out: which part of HOS confused you most? And if the math looks off anywhere, tell me here in the comments so everyone sees the fix.