Life ‘BC’ – or ‘Before Children’ – is £400 a month cheaper, according to research.
A poll of 2,000 adults found an average month costs around £1,406 for those with one or more children.
But childless couples can get by with an expenditure of just £1,006 each month.
The single biggest cost of having a child was found to be in moving up to a bigger mortgage and coping with the higher household bills, setting parents back more than £8,677 a year.
By comparison, those without kids face an annual bill of £6,025 for rent, mortgage or utilities.
And buying shoes and clothing set parents back a further £471 a year – around £164 more than it costs those without kids.
Simon Wilson of Deichmann Shoes, which commissioned the research, said: “As a parent myself I know that having kids is really rewarding, but also very expensive.
“If only there was such a thing as ‘parent points’ on your credit card.
“From the moment you find out you are expecting, there are suddenly a host of extra costs you wouldn’t have had if it wasn’t for the kids.
“All the little things add up over time and its especially difficult to keep up with clothes and shoes as children keep growing.
The average British family’s food bill also shoots up an incredible 25 per cent after having children from £2,622 to £3,375 a year.
And holidays will go up from £1,767 to an average of £2,257.
The amount spent on birthday gifts and leisure activities will also rise after having children.
But the study, commissioned via OnePoll, found that while many areas increase in cost when having children, parents will spend less on alcohol and nights out.
Guilt creeps in though with two thirds of parents admitting they feel bad spending spare money on themselves compared to just 48 per cent of those without children.
Despite the huge increase in expenditure, parents are most likely to miss sleep and free time most from their life ‘BC’, with 37 per cent longing for these days compared to just a third who miss the financial benefits.
However, almost three quarters also said having little ones was the best thing they’ve ever done.
And while only a fifth of parents felt financially ready to have children when they did, seven in 10 don’t believe you can ever truly have the ‘right’ amount of cash to start a family.
Simon Wilson added: “We hope our value offering will help parents out, either allowing them to treat themselves or buy another pair for their little ones.
“Our stores offer fashion-led shoes for all the family and our price guarantee means that we will refund the difference if you find an identical pair of branded shoes cheaper in any UK high street or online retailer.”
* At Deichmann, shoes are presented in a special “rack-room” concept so the customer is not presented with single shoes arranged on the shelf by size meaning you no longer have to ask the sales assistant to get the shoe in a different size or colour.
Top 10 biggest expenses for parents:
1. Paying rent/mortgage
2. Paying bills
3. Buying food
4. Holidays and trips away
5. Buying clothes
6. Cinema trips
7. Gym memberships
8. Buying shoes
9. Sports clubs
10. Buying alcoholic drinks