It costs at least £148,000 to raise a child to age 18 – or around £160 a week – according to research by the Child Poverty Action Group and the Joseph Rowntree Foundation.
The overall cost, which includes childcare and housing, increased by 4% in 2013, at a time when Child Benefit did not rise at all; while other state benefits for families and children rose by just 1% and average earnings by just 1.5%.
The research pointed out that the value of both Child Benefit and Child Tax Credit relative to the costs of raising a child decreased over the past year.
Meanwhile, the cost of childcare alone rose by 5.9% over the past year.
The Child Poverty Action Group said minimum-wage families now face a growing shortfall for the spending their children need.
Working families, where both parents work full-time on minimum wage, are facing an income shortfall of 17%, while lone parents working full-time face a 13% shortfall.
Those families receiving out-of-work benefits face even greater shortfalls of income, with couples needing a further 42% to cover minimum costs and lone parents 39%.
Squeeze on families
Alison Garnham, chief executive of Child Poverty Action Group, said: "This research paints a stark picture of families being squeezed by rising prices and stagnant wages, yet receiving ever-diminishing support from the government over the course of the last year.
"Every parent knows it's getting harder to pay for the essentials their children need, and they don't feel like politicians see them as a priority. Child benefit and child tax credit have been cut at the very time families need them most. Families are getting worse off and parents know it.
"If every child in Britain can grow up healthy, well-educated and an active participant in their community, we all benefit from a more prosperous economy. This was well understood by the post-war generation who prioritised universal benefits for all children despite being much deeper in debt than we are today."
Katie Schmuecker, policy and research manager at Joseph Rowntree Foundation, added: "The task of making ends meet for families with children has always been hard, but is getting harder, and balancing family budgets has become a perilous and delicate act for hard-pressed parents.
"Flat lining wages, cuts to benefits and tax credits and the rising cost of essentials is creating a growing gap between income and needs."