U.S. consumers remain upbeat about the economy as 2014 draws to a close, according to a survey of households released Tuesday. Optimism about the future picked up further.

The Thomson-Reuters/University of Michigan final December sentiment index slipped slightly to 93.6 from a preliminary level of 93.8, according to a source who has seen the numbers. Both December readings are well above a final November reading of 88.8.

The end December reading is near the 93.8 reading expected by economists surveyed by The Wall Street Journal.

This month’s final current conditions index fell to 104.8 from the early December reading of 105.7. The expectations index rose to 86.4 from 86.1. Expectations are at their highest reading since January 2007.

Household confidence has risen since the summer, coinciding with the steep drop in gasoline prices. Cheap energy along with a stronger pace of hiring has provided a financial windfall to consumers.

Additionally, with gasoline prices down, inflation expectations remain low.

According to the Michigan survey, the final December one-year inflation expectations edged down to 2.8% from the 2.9% expected earlier this month. Inflation expectations covering the next five to 10 years also fell to 2.8% from 2.9%.

Write to Kathleen Madigan at kathleen.madigan@wsj.com