New estimates released Friday put the cost of renovating and expanding Martha’s Vineyard Regional High School at $333.5 million, with potential state reimbursements dropping Islanders’ share of the total to between $253 million and $256 million.

Earlier estimates had put the cost at more than $350 million, but financial analyst Sidni Bragg of CHA, the school’s project manager, said the latest design contains more renovated space, which the Massachusetts School Building Authority (MSBA) reimburses at a higher rate than new construction.

The high school building committee got its first look at the new numbers Friday and will meet again Tuesday to finalize its submission to the MSBA, which will decide early in 2026 whether or not to grant reimbursements for close to $78 million.

The new estimates are based on a schematic design by Tappé Architects that calls for renovations throughout the 66-year-old school and the addition of a two-story classroom building on the west side of campus. The district’s preferred design would preserve the performing arts center, the gymnasium and the spaces connecting them; the rest of the existing school would be demolished to make way for the new academic building.

The high school committee is due to vote on the submission Wednesday, before submitting it to the MSBA by the Dec. 18 deadline.

Should the state authority accept the high school project for reimbursement, a majority of Island voters will need to approve the plan at a special election, provisionally scheduled for June 2.

All six towns agreed in 2022 to a cost-sharing formula for the building project, based on a mix of the property values and admissions statistics in each town.

CHA project manager Michael Owen told the building committee Friday that he will have the individual towns’ estimated costs in time for Tuesday’s building committee meeting.

Construction expenses alone would add up to more than $314 million, according to Friday’s presentation by Ms. Bragg and Mr. Owen.

Another $8.6 million would fund a solar energy package, with rooftop arrays, parking lot canopies and an one-megawatt generator, that’s not included in the current design.

Mr. Owen said CHA had prepared the numbers at the building committee’s request, as members considered whether or not to include the solar installations as part of the construction project.

“It will offset your operational expenses in an all-electric high school,” he said.

If the committee decides it wants the solar work, it will need to add it to the design in the application due next week, he said.

Legal, insurance, permitting and architectural fees, along with the cost of outfitting the school with new furniture and equipment, are among the project’s other costs.

The estimated project budget includes the $2 million feasibility study Island voters authorized in 2023 as the first step toward entering the MSBA grant program.

There also are contingency funds in the event of unforeseen cost overruns.

The new cost estimates put the MSBA’s reimbursements at $78,620,194, although Ms. Bragg said the state authority usually pays out about three per cent less than the total grant due to expenses deemed unreimbursable after the fact.

School officials have been pursuing a new building for several years due to outdated heating systems and other infrastructure, a lack of space and a leaky roof.