Bosses from the world famous school told MSPs they were confident that the insurance claim, cash from the Scottish and UK govern-ments and public donations would meet the bill to restore the Mackinstosh building to its original cond-ition after it was devastated by fire last month.
Professor Tom Inns, director of Glasgow School of Art, told the Scottish Parliament education committee the final figure would be known only once full access was granted to the building.
He said: "We estimate somewhere between £20m and £35m, but have not had full access to do a full estimate. It is still being secured by building control."
He agreed with the estimate by the fire service that 90% of the building and 70% of the contents had been saved.
As reported in later editions of the Evening Times yesterday the Scottish Government has granted £750,000 for a Phoenix bursary to allow students who lost their degree work to create new work.
Professor Inns said it would cover living costs, studio rental and help with materials to allow them to produce new work and show it as they lost out on the opportunities afforded by the annual degree show.
He said: "That is where they show their work and sell work and make professional contacts."
He said they would get the opportunity to show new work in March, thanks to the bursary.
The Mackintosh building will be out of action for around four years and students will need to be accommodated in other areas until then.
Prof Inns said it is looking for suitable alternatives and the other universities in the city and Glasgow City Council have been helping.
He said the council responded immediately with help to house salvaged items while the building was still ablaze.
He said: "We had fantastic support from the city council, particularly from Gordon Matheson who went there on the Saturday.
"I asked for help on the Friday and told him we needed it now and we were given access to the McLellan Galleries.
"That support has been ongoing as we are looking for places to take students for the decant and the other universities have responded likewise."
The council said it would be helping with student space.
Mr Matheson, leader of Glasgow of Glasgow City, said: "The Glasgow School of Art deserves our full support as it recovers from the impact of the recent fire.
"The council immediately offered a range of support services including the use of the McLellan Galleries, which has allowed the School of Art to once again showcase the work of its final-year students at the annual degree show.
"We are also working with the School of Art to look at providing suitable class-room accommodation for students to allow them to continue their studies over the coming months while the building is restored."