Calculations based on leaked documents suggest that US Uber drivers are barely paid above the minimum wage in some states Reuters

Data taken from leaked internal documents has suggested that some Uber drivers in the US are making less than their state's minimum wage. According to a report, Detroit drivers make just $8.10 (£6.09, €7.33) an hour – 40 cents less than the state's minimum wage.

The data for Detroit, Houston and Denver reported by Buzzfeed News lists Uber payscale and driver history files, and estimates hourly wages while taking into account expenses such as insurance, vehicle maintenance and fuel costs.

Despite these initial calculations, a Washington Post report lowered the meagre earnings figures further. As Uber drivers are technically independent contractors and not direct employees of the online taxi service, the drivers also pay out twice the amount of standard tax for usual workers.

After factoring this into its calculations – as well as the average hourly mileage costs for travelling to a pick-up spot without a passenger – Detroit's drivers were estimated to earn $6.60 an hour, with Houston and Denver following at $8.43 and $11.21 respectively.

The paper spoke to an anonymous Uber representative regarding the initial report, who said "It would be wrong, or at least very challenging, to calculate expenses with such a diverse clientele."

The spokesman also questioned how the San Francisco-based company could accurately "calculate expenses when drivers make individual choices for their vehicles?", explaining that "fuel expenses are wholly different between the two. Insurance costs are different. The cost of tyres are different."

Washington Post also spoke to Lawrence Mishel, the president of the Economic Policy Institute, a DC-based think tank. Mishel stated: "Uber likes to play it both ways. It claims that it's the future of work, while it also emphasises that most of the drivers work less than 10 or 12 hours a week. They want to be the wave of the future, but they also want to picture themselves and their drivers earning [extra] money."

While the calculations are only applicable to Uber drivers in the US, this isn't the first time accusations of low levels of pay has been levelled at the app-based taxi firm.

In February, IBTimes UK spoke to James Farrar and Lucas Malec – two UK-based drivers disillusioned by Uber's commission rates and overall support. Farrar in particular estimated that after expenses he earned just £5.03 an hour – well below the £7.20 for UK workers over the age of 25.

While Uber has recently settled two class-action lawsuits in the US in Massachusetts and California, this was followed by further legal challenges claiming that the company violated the Fair Labor Standard Act.