I'm three months in as a tech lead for a relatively small (~100 people) but successful and grounded consulting company in a major U.S. city. Due to poor requirements gathering coupled with underestimations by the architect and director, one of my projects hit the ground stumbling.
I've consistently worked overtime in order to try and right the wrongs of other people and get this ship back on course and have only billed my company for 40 hours each week. This act doesn't seem uncommon as a consultant or contractor because we usually sign clauses that explicitly say that overtime work and pay must be approved by your manager. So if you want to get the project back on track and avoid writing spaghetti code under deadline pressure, the choice is to usually work unpaid OT. Ultimately I make a great rate and like the project so it hasn't been a big deal.
Three weeks ago I got a text from the Director saying,
"We really need you to put in 6 hours on Client X but can't afford to take you off Client Y either. If you'd be willing to, feel free to put in extra hours this week."
I understood that to mean, "You've been given permission to bill the company for overtime." and so that's what I did - I logged 46 hours in our timekeeping app for that week.
But when my paycheck arrived, I discovered that I was paid for 46 hours at my normal rate. Apparently in my state, companies can elect to not pay overtime rate to computer-based employees that make over ~$30/hr. Of all the companies I've ever worked with, this is the first one to elect not to pay an overtime rate. After reviewing HR documents, I noticed that they're also the first I've seen to not have any clause in the contract that says we must ask for permission before working overtime. With that in mind, this has completely changed my feelings on working unpaid overtime.
Last week - I had dumped in 56 hours in a final push to get a fantastic client demo out with all the requirements higher-ups promised to deliver on. I had every intention of just billing 40 hours because I didn't want any assumed conflict that comes with bringing up overtime pay at 1.5 times the hourly rate. But now that I know that they don't pay out an overtime rate, I want to bill those hours.
My intuition says the company will ultimately have a major issue with this because when a project is bid to a client, it's under the assumption that I, or my team, is working at periods of 40-hours-per-week. On the other hand, I feel pretty burned by not being paid my overtime rate.
Considering I don't make an overtime rate, would it be a bad decision to charge for 16 extra hours without permission?
 United States: any hours billed past 40 hours per working week usually require overtime pay of 1.5 times the employee's hourly rate. Read the whole post for insight into the "usually".