St Michael and All Angels Parish Church in Haworth, West Yorkshire, had raised the £65,000 needed to secure £100,000 in funding from English Heritage.
But rising costs of building work now means it requires up to £50,000 more.
John Huxley, secretary at Haworth church, said: “We were overjoyed to learn we had reached the total, then knocked sideways by finding out building costs had gone up by so much.
"The reaction from the public to help raise funds has been absolutely phenomenal."
The church said a meeting would be held on Tuesday to discuss further fundraising options.