Schoolchildren face the prospect of a four-day week because of a shortage in funding, a group of head teachers said.
Speaking to the BBC, five school principals from Cheshire also warned some subjects could be scrapped, while teaching assistants and mental health support workers could face redundancy.
In December, the government announced the biggest shake-up of the school funding formula for decades.
Ministers said it would resolve "unfair" and "inconsistent" funding.
The new formula would mean less money for schools in big cities, which have traditionally received higher levels of funding.
Head teachers in West Sussex have made a similar threat to cut school hours because of "dire finances".
Schools in some of the worst-funded areas, including Cheshire East and Trafford, could also lose out.
According to analysis carried out by Cheshire East Council and head teachers in the borough, overall school spending would be cut by 2.1%, taking the basic level of funding per pupil to the lowest in England.
Expanding upon the four-day week idea, Holmes Chapel Comprehensive School head teacher Denis Oliver said he was investigating the possibility of "having children working at home with their teachers online as virtual support, [thereby] saving on heating, lighting, cleaning and transport costs."
"We are looking at everything," he told the BBC.
"Class sizes will rise, services for children with high needs will drastically reduce, school libraries may have to close.
"It's draconian. It will destroy some schools."
Nearby Alsager School is set to lose about £150,000 - 2.9% of its budget - and is looking at cutting some subjects.
In a recent letter to parents, head teacher Richard Middlebrook warned the new formula could mean "the removal of all non-English Baccalaureate subjects from the curriculum".
This would mean subjects including art, music, drama and design and technology being axed.
"The very future of our school and the quality of education your son or daughter will receive at Alsager is at stake", he warned.
A Department for Education spokesman said the current system for distributing school funding was "unfair, opaque and outdated and the proposals we are currently consulting on will mean an end to this postcode lottery".
The spokesman said the plan would mean a cash boost for more than half of England's schools by 2018-19.
"We recognise that schools are facing cost pressures, which is why we will continue to provide advice and support to help them use their funding in cost-effective ways," he added.