All regular public school students across the state will be returning to school on July 27 next year, following a unified calendar for the first time since schools began experimenting with modified year-round calendars 17 years ago.

Under the calendar adopted by the Board of Education on Thursday, students will attend school from July 27 through June 7, with a week off in the fall, three weeks in the winter and two weeks in the spring.

The unified calendar is one of the reform measures called for in the Reinventing Education Act of 2004.

The BOE voted down another element of the act at the same meeting: the latest proposal for a weighted student formula intended to make the distribution of money more equitable and better targeted at students who need extra resources.

The board is under pressure to pass a formula soon — the self-imposed deadline passed in May — so that schools can put together the academic and financial plans they must submit to area superintendents before the winter recess.

"We got to a certain point where we really really need to make a decision," said BOE chairman Breene Harimoto. "It was not approved and I'm very disappointed."

The weighted student formula would set a base dollar amount for every student, then provide additional money for students who need extra resources, such as those from low-income families, who are learning to speak English as a second language or who require special education classes.

But board members are concerned that the new formula will mean losses upward of $100,000 at some schools. "Emotions run high when schools say, 'I'm losing 30 percent of my budget,' " Harimoto said.

Schools began to panic when they saw a version of the formula released this summer that would mean 94 schools would lose more than $100,000 annually and 77 would gain more than $100,000 a year.

Harimoto said he does not know what the next step is now that the BOE has voted down the formula presented by the Committee on Weights and the Department of Education.

Tweaking any part of the formula to satisfy some concerns will inevitably create more problems because something else will be affected, he said.

While Harimoto intends to have a revised version of the weighted student formula before the board as soon as possible, further delays could mean that principals will have to put together their financial plan for next year at the last minute, or perhaps without even knowing what their budgets will be.

"Schools are really under the gun and now have to do a whole lot of work in a very short period of time," he said.

Reach Treena Shapiro at tshapiro@honoluluadvertiser.com.