Con Ed electricity rates are heading up about 2.5 percent next month — a smaller increase than originally expected.

Monthly bills will rise $2.26, to $92.78, for typical New York City apartment dwellers who use 300 kilowatt hours of electricity under the plan approved today by the state Public Service Commission.

That’s less than the 3.7 percent increase called for in a three-year Con Ed electric rate plan approved by the commission in 2010.

The smaller increase is possible because Con Ed’s spending is under budget, and because of lower local and federal taxes.

Con Ed’s new rates for its 3.3 million electric customers in New York City and Westchester will take effect April 1.

The PSC’s decision today is in line with a request by Bloomberg administration officials. Con Ed had suggested a smaller rate rollback.