The research calculates that the cost of heading back to school for parents across the UK has reached £2.5 billion a year. This includes clothes, books, stationery and other necessities.
The research, which has been commissioned by Santander, also claims that the cost of keep under-18s across the UK in school once term begins totals £526 million a week – roughly £50 per child, per week.
Weekly school costs include packed lunches, bus fares, school trips and after-school clubs and activities.
The figures are for the 2014/15 academic year and are up seven per cent on similar research from 2013/14, when the cost of preparation was £224 per child.
The research has been compiled based on interviews with 2,002 adults from across the UK who have children at school aged between four and 17.
Excluding private schools, parents with children at grammar schools pay the most – an average of £265 in preparations and then £64 a week during the year. Meanwhile, parents with children at community schools pay £250 and then £51 a week.
Breaking down the costs, school uniform – at an average of £39 a time – shoes (£29) and jackets and coats (£28) are the biggest outlays.
During the school year, school trips (£10 a week) and packed lunches, extra-curricular activities and school meals (each of which average £8 a week) are the most expensive.