WASHINGTON, March 13 (Reuters) - U.S. consumer sentiment ebbed in early March as war in the Middle East raised gasoline prices and households worried about personal finances, a survey showed on Friday.

The University of Michigan's Surveys of Consumers said its Consumer Sentiment Index fell to 55.5 this month from a final reading of 56.6 in February. Economists polled by Reuters had forecast the index falling to 55.0.

The survey was conducted between February 17 and March 9, with about half completed after the start of the U.S.-Israeli war with Iran. The conflict has boosted oil prices. Gasoline prices have soared more than 21% to $3.63 per gallon since the war started, data from motorist advocacy group AAA showed.

"Interviews completed prior to the military action in Iran showed an improvement in sentiment from last month, but lower readings seen during the nine days thereafter completely erased those initial gains," said Joanne Hsu, the director of the Surveys of Consumers. "A broad swath of consumers across incomes, age, and political affiliation all reported declines in expectations for their personal finances, down 7.5% nationally."

The survey's measure of consumer expectations for inflation over the next year was unchanged at 3.4% this month. Consumers' expectations for inflation over the next five years dipped to 3.2% from 3.3% last month.