On average, for three and four-year-olds, childcare costs Â£ 4.00 an hour.
For two-year-olds it was slightly more expensive, at Â£ 4.25 an hour.
Across Yorkshire and Humber the most expensive childcare for three and four-year-olds was in Barnsley and Sheffield, where the average cost was Â£5.00.
Kirklees was the cheapest at Â£3.75 per hour.
Every three and four-year-old gets 15 hours of free childcare a week, and 30 hours for those with parents who both earn the equivalent of 16 hours at the minimum wage.
Two-year-olds with parents who receive welfare benefits also receive 15 hours free childcare a week.
Gingerbread, a charity which supports single parents, called on the Government to increase its 30 hour offer to those in education, training and on zero hour contracts.
Dalia Ben-Galim, the charity's director of policy, said: 'Thousands of single parents are currently locked out of work due to unaffordable childcare.
'Gingerbread's research shows that some single parents spend roughly half their take-home pay on a nursery place and they consistently tell us that it doesn't always pay to work.'
Ms Ben-Galim explained often single parents were choosing not to work as it was 'too risky or doesn't add up'.
"Gingerbread is calling for the Government to change the eligibility criteria for its flagship 30 hours offer for three and four-year-olds to cover those in education, training and on zero-hour contracts,' she said.
'This would go some way in reducing some of the barriers that are blocking single parents from entering high quality, secure employment.'
Across England the average cost for three and four-year-olds was Â£4.92. The most expensive place was Westminster, costing Â£8.50 an hour, and the cheapest was North Tyneside, costing Â£3.50 an hour.
Neil Leitch, chief executive of the Pre-school Learning Alliance, called on the Government to put more funding into childcare, as the financial pressure on providers could increase.
Children and Families Minister, Nadhim Zahawi, said: 'We want every child to have the best start in life, with access to high-quality childcare and early years education.
'Ofsted data shows 94 per cent of childcare providers are rated good or outstanding.
'Childcare and early years settings across the country are successfully delivering our 30 hours offer which is bringing significant benefits to families.'
The minister explained that more than 340,000 children had received a 30 hours place, since the scheme started last September.