I need a formula that will sum Log In and Log Out, remove 0.5 hours for lunch, even if less is taken, but also sum any additional lunch time over 0.5. People will be required to take a half an hour lunch, even if they don't take one at all, or take less than 0.5, but we need to subtract from daily hourly totals if they go over.

I'm currently using =SUM((H4-C4)*24)-0.5, but can't figure out how to always subtract 0.5 hours, but also subtract if the user goes over 0.5 hours.

Any help would be greatly appretiated. I haven't worked with an Excel formula in five years.