The biggest boom is in key stage test papers as the country's seven and 11-year-olds cram to achieve literacy and numeracy targets.
Fear of failure is pushing parents to buy more study materials for ever-younger children, say publishers. Sample papers for 11-year-olds ranked in the top 15 non-fiction bestsellers last month, while GCSE revision guides outsold even fiction titles.
More than 600,000 guides and practice papers have been sold by one publisher while WH Smith's test paper sales are up by more than 10 per cent on last year.
Nearly 1.2 million 11 and 14-year-olds will sit tests in English, maths and science next month. while seven-year-olds are preparing for English and maths tests.
Fiona Williams, of WH Smith, said: "Parents are worried that if their seven or 11-year-old falls behind in maths they will never be able to get a job."
Maths is the biggest worry with 12,600 copies of practice papers for 11-year-olds sold in the first 12 weeks of this year, according to Whitaker BookTrack which monitors sales in 4,600 shops. Last year only 5,275 copies sold in the same period, excluding WH Smith.
Susan Wakefield, of BookTrack, said: "It is quite incredible for a revision guide to make the top 100 in the bestseller list. The rapid expansion shows the pressure that is on children at all levels."
Hayley Lewis, of Letts Educational, also warned there is a danger of overload: "We advise parents that it is better to buy practice papers rather than cramming too much content very late in the day."