The average monthly income of a UK family reached £2166 in December, marking the highest figure seen since Aviva's regular family finances report started in 2011 and following 18 months of increases.
Family incomes have risen by 12% since January 2011 when the typical family took home £1937 a month.
But families are now separated by a bigger income gap than in January 2011. Three years ago the difference between average monthly incomes of the highest and lowest earning types of family was £1281. That gap has increased by 14% to £1459 in December 2013.
Those with the highest average incomes are couples with plans to have children, who take home £2422 typically. Single parents with one child or more have the lowest typical income at £963.
Researchers found that couples with no plans for children take home £2284 a month on average, couples with one child bring in around £2321 and those with two or more children have £2301 typically. Families' changing fortunes mean that couples with one child have gained the most over the last three years.
Their gains are in stark contrast to divorced, separated or widowed parents who have seen their incomes fall by 14% over the same period, the report found.
Louise Colley, protection distribution director for Aviva, said: "Growing incomes mean some families will be starting the new year in a better financial position than they have become accustomed to.
"But sadly the widening gap between the 'haves' and 'have nots' means this cheery outlook will not be shared by all."