The Cambridge School Committe on Thursday tentatively recommended a $24.5 million budget for the coming year, representing an increase of only $920,000 that will ultimately result in cutbacks due to increased costs, a committee member said yesterday.

Glenn S. Koocher '71, the committee member, said the 4-per-cent increase actually represents a decreased real outlay because it will fail to cover even next year's already-approved 6 per cent teachers' salary increase.

Salaries comprise about 85 per cent of the budget, he said. Koocher added that the austerity budget will only cut inefficiency and should not affect educational quality.

The budget will require cutbacks in the number of teachers and supporting staff through attrition, Albert H. Giroux, director of public information for the school department, said yesterday.

Giroux said Cambridge currently has low teacher-to-pupil ratios, so the cuts can be absorbed by a more efficient utilization of staff.

Property tax rates will rise by about $3 if the school budget increase is financed by a tax increase, Koocher said.

The committee will finalize the budget proposal Tuesday night and then send it to the City Council for approval.

Mayor Alfred E. Vellucci said Thursday night he is "sure" there will be no problem getting the council to approve the budget.