One in 10 single people says their finances are out of control, a survey for a financial advisers group says.
Buying a home is believed to be a trigger for sorting out finances
Most cannot or will not save more than they do, with one in four not thinking about how the present affects the future, says the IFA Promotion survey.
Four out of 10 said they had suffered a financial crisis at some point, compared with 28% of married people.
The report suggests rising ages for getting married and buying a home mean people put off sorting out their money.
IFA Promotion, which supports the work of independent financial advisors, commissioned a BMRB poll of 2,000 people.
Many single people questioned said they simply enjoyed spending their money, while others said they were paying off debts.
Nearly three-quarters of people aged 25 to 34 admitted they did not even know what their financial situation was.
Buying a property can be a major trigger for sorting out finances, and the report found three times as many people renting felt out of control with their money compared to those with mortgages.
The research also found more than half of adults across all age groups said they were not prepared to cut back spending to save more for retirement.
IFA Promotion's chief executive David Elms said retirement may seem a long way off for people in their late 20s and early 30s, but not planning a pension in time would have a "serious effect" on future lifestyles.
"We are delaying important life events such as marriage and mortgages until later in life but this doesn't necessarily mean we want to work into our dotage because we can't afford to retire," he said.
"The only sure-fire way to solve this dilemma is to take some responsibility for your long-term finances now and get saving."