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You already have a car. You know how to drive. Why not get into the lucrative Uber game? It’s not an uncommon thought. If you’ve ever spoken to your Uber driver, many of them seem to take up the gig to cover the cost of their car. But can you earn a decent living driving drunk idiots around your hometown?

The website NerdWallet actually crunched the numbers, looking at what it would take to earn $50,000, $75,000 or even $100,000 working for the companies Uber, Lyft and Sidecar.

How many rides does it take to pay for insurance?

Here’s the breakdown. The average Uber fare is $15.97. That means to make an annual gross income of $50,000, a driver would need to give just over 60 rides a week. But that doesn’t include the cost of maintaining the car. Using a 2014 Toyota Camry as the base model, it takes 1.32 rides a week to cover insurance and 6.11 rides a week to cover the cost of car ownership.

Now, some hard math: the average Uber trip was 10.2 minutes. Therefore, a driver could make $50,000 by driving just 20.47 hours each week. Not a bad gig – until you take utilization rates into account. NerdWallet points out that “ ’driver utilization’ for New York City’s yellow cabs is about 50 percent, which means that for each hour drivers work, they are ferrying passengers 50 percent of the time.” By that standard, drivers are suddenly looking at a full 40-hour work week (again, just to get a gross income of $50K), though anecdotal evidence reveals that Uber drivers’ utilization rates may be even lower than those of a yellow cab.

Also, rates vary significantly from city to city. Looking at 14 different markets, it would take nearly twice as many rides to earn the same amount in the most lucrative market, San Francisco, as in the worst market, Charlotte, N.C.

The moral is: if driving is your thing, Uber seems like a fine way to make some cash. But if you’re looking to start taking a ride down easy street, as the old saying goes, don’t quit your day job. Unless, of course, your day job pays less than $50,000 a year and requires you to work more than 40 hours per week.