Mayor Michael R. Bloomberg proposed a budget Friday that would increase the city’s sales tax by half a percentage point as the centerpiece of $1 billion in new taxes to help the city avoid deeper spending cuts and minimize layoffs.

Even clothing, which has long enjoyed at least a partial exemption from the city sales tax as a way to make city retailers more attractive than their suburban counterparts, would be subject to Mr. Bloomberg’s proposal.

If approved by the City Council and the State Legislature, the increase would apply to the city’s portion of the sales tax, which, when added to a state tax and transit tax, would lift the total rate to 8.875 percent, one of the highest in the country. Only once since 1974 has the city’s part of the sales tax gone up, and that was a temporary 0.125 percentage-point increase from 2003 to 2005.

But this time, Mr. Bloomberg did not utter the word “temporary.” So if the proposal is enacted, a typical household in New York City making $35,000 a year would have to pay an extra $129 a year in sales taxes, clothing included, according to estimates by the city’s Independent Budget Office. A household making $125,000 would pay an additional $356 a year, and one making $500,000 would pay $840 more.