The figure was revealed by a TaxAction investigation on behalf of independent financial advisers and said financial inertia and ignorance of the tax regime were to blame.
And nine out of ten UK taxpayers or 41 million people, are believed to be £140 worse off as a result.
The group advised that four million people on lower incomes could each save themselves £75 tax if they completed an R85 form, which prevents banks and building societies deducting tax from interest payments. People falling within the self-assessment scheme filing their returns on time could save a further £1.12bn.
Crowe Clark Whitehill , the top 20 accountancy firm, has announced the promotion of Chris Mould to partner
The latest opinions from Accountancy Age on Making Tax Digital, and outline plans to evolve the UK's corporate governance regime
Five million taxpayers are ow using digital personal tax accounts (PTA) as part of the making tax digital strategy, HMRC said
UK-based non-doms have paid ten times more tax than the average taxpayer, raising concerns over the Brexit impact on non-dom contributions and therefore, the economy