On top of spending 51 hours caring for people, mothers also spend 25 hours a week doing the housework.
That's 76 hours of work a week in the house alone - that's not even counting the time mothers spend doing actual paid work.
Those with no children only spend about 16 hours a week on housework like cooking, cleaning and washing.
The Australian Institute of Family Studies discovered the majority of women reported they were tired, and it's pretty clear why.
About 40 per cent of women with preschoolers said they were tired, worn out or exhausted from meeting the needs of their children.
Institute director, Anne Hollonds, said children were a dramatic change in a woman's life.
"There is a huge change for women who virtually overnight start wrestling with far greater caring responsibilities than they have ever had to confront before," she said.
Ms Hollonds said most women increased their time at home once giving birth and spent less time in the office, allowing them to do extra work around the house.
While it never really ends for a mother, there comes a time when she can relax her responsibilities.
When a woman's youngest child starts school, she will care for others for about 26 hours a week.
Once the children leave home, a mother will spend five hours a week caring for others.
Australian Institute of Family Studies senior research fellow Dr Jennifer Baxter said while the number of hours spent caring for others dropped once a child went to school, a mother would always spend a ridiculous number of hours a week doing the housework.
"Even in the year after all the children have left home, housework still consumes 25 hours a week," she said.
The labour of love that comes with being a mother is something political commentator and mother of three, Annabel Crabb, knows all too well.
In her book, The Wife Drought, she spoke about how women needed wives as only three per cent of fulltime working mothers in Australia had a partner who either worked part time or not at all.
She talks about gender roles in bringing up children and the hardships working mothers face.
"If you are working fulltime, and your spouse is working either part-time or not at all, then - congratulations! You have a 'wife'," she said.
"A wife, traditionally, is a person who pulls back on paid work in order to do more of the unpaid work that accumulates around the home.
"This sort of work goes into overdrive once you add children to the equation, and the list of household jobs grows exponentially to include quite specialised work such as raising respectful, pleasant young people, and getting stains off things with a paste of vinegar and sodium bicarbonate."
Crabb said a "wife" could be male or female and said they were a "cracking professional asset".
"They enable the busy fulltime worker to experience the joy and fulfilment of children, without the considerable inconvenience of having to pick them up from school at 3pm, which - in one of the human experience's wittier little jokes - is the time that school ends, a time that is convenient for pretty much no one."
Ms Hollonds said being a mother was a daunting prospect for those wondering how they were going to shoulder most of the childcare and housework, while being encouraged to get back into the workforce as quickly as possible.
"Apart from being a fairness issue, pressures on mothers may affect the quality of family relationships. It's time for more equal sharing of domestic chores to be seriously addressed as an economic and social issue affecting all families raising children," she said.
