Homes, cars, weddings and new babies all add to debt, with Axa Wealth Management claiming that spending hits £32,441 at 34.
“While 34 was on average the most expensive year in life for all Britons, this study demonstrates that people of all ages face peaks in outgoings which see them having to cope with major expense at different times in their lives,” said Axa spokesman Colin Nelson.
With different demographic groups surveyed about their spending patterns at different ages, other years also incurred large bills.
At 26, many people spent money on cars, holidays and honeymoons, while at 43 peak debt was due to home improvements and putting children through university.
While 34 is the overall peak, the survey highlights that debt and spending occurs at all ages, but often for different reasons.