When asked to identify their biggest financial mistake, 5% of respondents said it was not buying a house, according to a study conducted by Hargreaves Lansdown.
The report also shows that 8% regretted not having invested, which rose to 12% among young people, and 16% answered not having started saving early enough.
Meanwhile, 9% regretted not starting a pension sooner, and 6% regretted not putting enough in.
As well as this, 7% said their biggest mistake was getting into unaffordable debt, and 5% regretted not paying off their debts.
Sarah Coles, personal finance analyst at Hargreaves Lansdown, said: “We all make financial mistakes, but some can be more expensive than others.
“Making mistakes with borrowing, saving and pensions can have far-reaching consequences for life.
“Our research shows that we’re kicking ourselves for failing to save enough for the future.
“The biggest financial regret, mentioned by one in six people, was not having started saving earlier.
“We also regret putting too little into our savings, and one in 10 women rue how little they have salted away.
“We all need robust savings to be financially resilient enough to cope with the nasty surprises life tends to throw at us.
“Meanwhile, almost one in 10 say their biggest financial mistake was not having started a pension sooner, and more than one in 20 regret not putting more into their pension.
“Whatever stage you’re at in life, it’s well worth using an online pension calculator to see where you stand, and whether you need to put more aside now to be able to afford the retirement you want.
“And there are plenty of people who say their biggest financial mistake was missing opportunities. 8% regretted not having invested, which rose to 12% among young people, while 5% regretted not buying a house.
“Fortunately, because we know the things other people are most likely to regret, we can learn from each other’s mistakes, and by working on each of the five pillars of financial resilience, we can protect ourselves from falling into the same traps.”