Mr Sunak insisted the Government was spending money on "things that we know are going to make the biggest difference" to help children recover from months of lost learning during the pandemic.
The Richmond MP has not denied refusing to pay for a £15bn learning recovery fund put forward by Sir Kevan Collins, the government’s education recovery commissioner.
Sir Kevan resigned after plans for a £1.4bn recovery fund were revealed and described it as woefully short of what was needed. His plan would have been spent on teachers, tutoring and an extended school day and included 100 extra hours of teaching per pupil to address lost learning.
The potential loss to the economy and country of lost learning is estimated to be as high as £420bn, with children in the most deprived areas likely to be the hardest hit.
Mr Sunak, who yesterday launched the new UK Infrastructure Bank in Leeds, told The Yorkshire Post the £3bn the Government has so far announced for catch-up and extra tutoring was "going to make a big difference".
And he said the Government had invested £14bn over three years into schools pre-pandemic which would mean "per pupil school funding returns to what are very high levels, historically".
Asked whether refusing to back Sir Kevan's plans was a false economy given the scale of lost learning, he said: "I don't think anyone in my job as a responsible Chancellor could just say yes to everybody who comes knocking on my door.
"And I think it's important for your readers to know that we should spend their money because it's not my money, we should spend their money on things that we know are going to make the biggest difference, and we're spending it on tutoring and we're spending it on making sure that teachers get the support they need to help kids in the best possible way.
"Now, all the evidence tells us that those are probably the two best ways we can help children, especially those disadvantaged children from poorer backgrounds, catch up on their lost learning.
"All the research and the evidence points to that, and we've maxed out, we've literally maxed out on what we can do in those two areas."
Asked whether Sir Kevan's proposals contained proposals he didn't think would be effective, Mr Sunak replied: "Look, lots of people put lots of ideas to us all the time. Our job is to figure out and prioritise and do the things that we think will work best.
"There's lots of things that might work, but what works best, where do we get the biggest bang for the pounds that we're spending, where can we make the most difference.
"And sometimes money is not really actually the constraint, it's what can be delivered, what can we actually deliver, particularly when you think about catching kids up.
"We're trying to do this quite quickly. We can't wait for years, and that's why whether it's tutoring or whether it's improving the quality and the resources that go into training teachers and helping them develop over their careers.
"We know we can deliver that over this period, and that's why £3bn of extra investment is going to go in and it really does make a difference.
"We've got lots of evidence and research from places like the Education Endowment Foundation that over the years have figured out that these things are the best things to do."The
Department for Education (DfE) has committed to a review of time spent in school, with findings due later in the year to inform the spending review.
And Scarborough born Education Secretary Gavin Williamson has suggested he is in favour of longer school days and that more investment for catch-up could be coming later.