According to a survey from PeoplePerHour, nearly a quarter of freelancers think they have been regularly overpaying the UK’s tax authority.

A third of those who are worried they have been overgenerous with their tax contributions think they may have overpaid by between £750 and £1,000, and PeoplePerHour calculates that this could mean some freelancers will be handing over an additional £50,000 throughout the course of their working life.

“If you’re not into your numbers, filing a tax return can be a nightmare, so I do have sympathy with those who find themselves paying more than they should,” said Xenios Thrasyvoulou, founder and chief executive of PeoplePerHour. “There is a lot to take care of when it comes to running your own business, keeping track of your finances is truly the key to success.”

Almost half of those surveyed said that they completed their return themselves rather than hiring accountant, and many said they were unsure what they could and could not deduct as an expense from their takings.

However, more than a third also admit to leaving their tax return until the 11th hour, meaning they could be more likely to make mistakes because they’re rushing to get everything done before 31 January.

Earlier this month, the Institute of Chartered Accountants in England and Wales warned those who were still yet to file their yearly papers not to leave it until the last second, pointing out that, as deadline day falls on a Sunday this year, help is less likely to be on hand to answer any crucial final questions.