But GDP growth still surpassed a White House target for two consecutive quarters and was the fastest expansion since the first three months of 2015.
Growth in the July-September period was revised down by a tenth of a percentage point to 3.2 percent, though it was still slightly faster the second quarter when the economy expanded 3.1 percent.
The news comes as President Donald Trump and Republican lawmakers celebrate the adoption of sweeping tax cuts which they say will boost economic growth in 2018 and beyond, though most economists say any gain is likely to be modest.
The downward revision from the GDP estimate published in last month reflected lower consumer spending, particularly in recreation and transportation services, the Commerce Department said in the third and final report on third quarter GDP.
Lower consumer spending, a key driver of the economy, was partly offset by higher spending by state and local governments on construction.
Analysts had been expecting GDP growth to remain unchanged from the second estimate released last month of 3.3 percent, which had marked the fastest quarterly economic expansion in three years.
Despite the small downward revision, the data confirmed the picture of a robust economy that did not even pause after back-to-back late summer hurricanes idled much of the petrochemical and oil industries in the Gulf of Mexico and forced millions to flee their homes in Florida.
Inflation-adjusted income rose two percent in the third quarter, slowing from 2.3 percent in the second quarter.
The US economy has been in recovery for the nearly a decade. Trump has hailed the recent rosy economic data as a vindication of his economic agenda, though his signature tax cuts have yet to take effect.
He has vowed to return the United States to sustained annual growth of three percent or better but the current pace is on track to finish the year significantly below this target.