Education cutbacks across the North West will reach more than £192m by 2020, according to the headteachers' union NAHT.
School leaders are gathering in Manchester to discuss what they describe as a "funding crisis". Their union says class sizes are already rising and teaching staff are being axed.
“There is a real concern that this will soon have a negative impact on children and education," says NAHT's General Secretary Paul Whiteman.
The summit comes a day after MPs announced a cross-party inquiry into school funding.