The Economic Policy Institute said the new federal minimum wage of $6.55 per hour is lower than the rate set by 23 states and the District of Columbia, CNNMoney reported.
The new wage still keeps a household of two with one full-time worker below the poverty line, the institute said.
"This reflects a stark reality in America: In the face of the rising cost of living for low-wage workers, the federal government is not guaranteeing a fair wage," Mary Gable, an EPI economist, said in a statement.
But some businesses owners see higher wages as inflationary.
"With inflation pressures increasing for small business owners, this is not the best time to be forcing employers to pay workers higher wages," said William Dunkelberg, chief economist for the National Federation of Independent Business.
Thursday's raise will still be welcome to millions, said a sponsor of the Fair Minimum Wage Act of 2007.
"The increase ... comes at an important time for the millions of Americans struggling to make ends meet," Rep. George Miller, D-Calif., said.