The state Board of Education today approved a costly proposal to remake Connecticut high schools by raising graduation requirements, requiring students to pass state exams in certain classes and ensuring every student has an adviser and an individualized plan of study.

The proposal, which will now be submitted to the legislature, comes amid a tough economic climate, with projections of a $300 million state deficit this year and lean times ahead. Over the next eight years, the plan is projected to cost the state $183.9 million, according to the state Department of Education.

A rough projection by the department also indicated that local districts could face millions of dollars in additional costs to hire more staff or build or modify schools to comply. Board members said they were mindful of the state's financial straits, but also said the need to better prepare students for higher education and the work force was too significant to delay.

The high school reform effort grew out of concerns that state test scores were stagnating and that high school graduates were increasingly unprepared for college and the work force. The state board of education passed a version of the plan last year, and a committee of educators, education and work force groups and state officials have refashioned it over the past year.

The plan the board approved today was scaled back from last year's proposal, in part because of financial concerns. Unlike the earlier version, this proposal would be phased in — implemented in 25 or 30 districts beginning with the next school year and statewide in the fall of 2013.

As proposed, the plan calls for increasing the number of required courses to 25, up from 20. It also lays out specific courses students must take and calls for students to complete a "capstone" project before graduating, which could be a portfolio of work, an internship or community service.

The proposal also addresses middle schools, requiring every student to have an adviser between grades 6 and 12, and to have an individualized plan to lay out courses of study and goals over those years. The adviser and student plan are part of an effort to increase student engagement and connection to faculty members, which board members said are critical to keeping students in school.

In five courses — algebra 1, geometry, biology, English 2 and U.S. history — students would need to pass a state-developed, locally scored final exam. Students who do not pass the exam would have several options, ranging from retaking the exam to taking a community college class in the subject.

Earlier versions of the proposal included a requirement that students take two years of world language before graduating, but that was not included in the version the board passed today. Several language teachers opposed the change at the board meeting, arguing that world languages are increasingly important for students entering the work force and that they help students perform in other subjects.

But several board members said the world language requirement would have made widespread support more difficult. The plan the board endorsed instead recommended that school districts begin language study in elementary grades.