The CPI was expected to rise 2.6% on an annual basis last month, according to economists surveyed by financial data firm FactSet.
The CPI tracks the changes in a basket of goods and services typically bought by consumers, such as food and apparel.
Inflation was unchanged in December from November's 2.7% annual pace, signaling that prices did not ease further at the end of the year.
However, cooling inflation did not translate into price relief. Prices continued to rise, leaving many households feeling pinched and complicating efforts to save for retirement or buy a home.