There are fears Kirklees schools are facing £30m funding cuts.
And a Kirklees union leader says teachers are already using their own money to buy school resources.
Cost predictions by the National Union of Teachers and Association of Teachers and Lecturers show the overall the budget change by 2020 could be £30,433,511 - if the government use a funding formula being considered.
They say it could mean the loss of £518 per pupil or 817 teachers, based on a teachers average salary.
But the Department for Education say they haven’t even crunched the numbers themselves yet and dismissed the figures as “irresponsible scaremongering”.
Hazel Danson, Kirklees NUT Secretary, said: “The figures are based on a possible funding formula that the government is considering using.
“It’s not us saying ‘these are the definite figures’. It’s us saying ‘this is what could happen if you use that formula to work out school budgets and you need to think again’.
“The impact of it would mean so many losses.
“Headteachers are already feeling the squeeze and feel more cuts are on the way. We think something may come on Wednesday in the Autumn Statement.
“The first thing to go will be non-teaching staff, support for individual pupils and classroom assistants.
“We know teachers are already using their own money to buy resources such as books and quality art equipment.
“We know that with funding cuts schools concentrate resources on core subjects that they are judged on, so it means schools may struggle to keep up a creative curriculum.”
A Department for Education spokesperson said: “This would appear to be irresponsible scaremongering, based on figures that are entirely speculative.
“In reality the schools budget has been protected and in 2016-17 totals over £40billion, the highest ever on record.
“The government’s fairer funding proposals will ensure that areas with the highest need attract the most funding and end the historic unfairness in the system.”
The funding formula has been slammed by Kirklees politicians, Clr Cahal Burke, Lib Dem, said: “Many schools will be under enormous pressure, and it could disproportionately affect smaller, rural and village schools.”
In a blog Kirklees Labour said: “Three of the Kirklees constituencies feature in the top hundred constituencies whose schools have lost most money in the government shake up of funding.
“The worst hit is Huddersfield who are set to lose 13% of their funding with a cut of £668 per pupil, closely followed by Dewsbury who will lose £534 per pupil, which is 12% of their funding, Batley and Spen will lose 11%, £510 per pupil.”
