Four out of five people are set to pay more tax than they need to this year, an Independent Financial Advice Promotion (IFAP) survey suggests.
Britons are not taking sufficient tax saving steps, the survey suggests
Failure to claim tax credits and poor inheritance tax planning are amongst the main reasons for people paying too much, the group added.
In total, the IFAP said that Britons waste £7.6bn a year in unnecessary tax.
David Elms, chief executive of IFAP, blamed public "apathy or confusion" for too much tax being paid.
"Over the past few years, the onus for managing tax affairs has shifted increasingly to the individual, but our awareness and action is not keeping pace, and so the mountain of tax waste keeps growing," Mr Elms added.
According to the IFAP, the main ways that people are missing out on tax breaks include:
- Failing to claim tax credits they are entitled to
- Forgetting to make simple IHT planning steps, such as writing life insurance into trust
- Non-taxpayers failing to claim back tax deducted from interest on savings
- Self assessment taxpayers missing the 31 January deadline for submitting their returns and automatically triggering £100 fine.
The IFAP surveyed more than 2,000 people about tax planning.