The wealthier you are and the higher qualifications you have, the more you will spend on tuition, according to a recent poll of 500 households.
Families who earned more than $6,000 each month reported that they spent about 30 to 50 per cent more than less-well-off families in their children's age group, from preschool to secondary school.
Graduate parents also spent up to four times as much on tuition as their counterparts with only primary school education.
Experts said research studies have shown that children whose parents are richer and more educated have advantages in terms of access to resources.
Associate Professor Jason Tan from the National Institute of Education said: "Studies in countries that have public and private schooling have shown that students in private schools seem to receive more tutoring than their counterparts in public schools.
"One explanation is that parents have disposable income for private schooling, and have already demonstrated their willingness to use the market to secure an educational edge for their children."
Prof Tan added: "So, in Singapore as well, this would apply. Richer parents are willing to pay more to secure an educational edge for their children."
For instance, those with monthly household incomes of more than $6,000 forked out a median sum of $200 each month on tuition for children in preschool, compared with $100 for those who earned $3,000 and below.
Similarly, those in the higher-income category with primary school-going children paid $300 each month, more than double the $125 spent by those less well-off.
Results from the poll also showed that more highly qualified parents spent more on tuition.
For instance, university-degree holders spent $500 on their preschool children, while those with only primary school education spent $100.
The study also found that more affluent families rated tuition more positively. Close to 40 per cent of respondents in the more-than- $6,000 income category said tuition had helped to improve their children's grades.
In comparison, about 16 per cent of those who earned below $6,000 felt the same way.
Housewife Hui Choy Leng, 52, said it is not surprising that families with more spending power would pay more for tuition.
"Not everyone can afford tuition," she said.
She and her husband, a retired chief executive, spend about $1,000 a month on mathematics and Chinese tuition for their Secondary 2 daughter.
"It helps to pull up her grades and addresses difficulties she has in understanding certain topics," said Madam Hui.
Madam Wong Peng Peng, 39, spends more than $1,000 a month on tuition for her daughters, who are in Primary 2 and 5. "When I look at their exam papers, I don't know how to help them," said the housewife whose husband is a partner in a shipbroking firm.
She added: "I don't mind spending as long as I can help my children to survive."