The tax gap, decomposed: how much is fraud, how much is honest error, and who it really sits with

A "tax gap" is one number governments publish for the difference between the tax that should be paid and the tax actually collected. Quoted on its own, it gets misused by everyone. Campaigners imply it is all corporate avoidance; ministers imply it is all fraud. It is neither. Take each country's official figure apart and you find the same uncomfortable shape: most of the gap is honest error and small-business non-compliance, a smaller slice is outright fraud, and the headline-grabbing corporate avoidance is, as officially measured, surprisingly small. That does not let the big structures off the hook. It means they are mostly measured somewhere else. This page does the decomposition, country by country, and says clearly what the number does and does not prove.

If you want the one-paragraph definition, it is on the glossary page. This page is the long version: each country's gap pulled apart into its components, with the corporate share marked, because the composition is the whole point and it is almost always misreported.

A warning before the numbers

The tax gap is a composite. It rolls together fraud, evasion, contested-but-legal interpretation, simple mistakes, and tax that was correctly declared but never paid. Reading it as a measure of corporate avoidance is wrong, and so is reading it as a measure of crime. We mark each component for what it is. We also flag the awkward fact the figures expose: the largest single chunk, in country after country, is small businesses, mostly through error rather than dishonesty. We are on the small firm's side, and the honest version of that position includes this number.

United Kingdom: £46.8 billion, and where it actually sits

HMRC's "Measuring Tax Gaps 2025" puts the total UK gap at £46.8 billion, or 5.3% of all theoretical tax liabilities, for 2023-24. Here is the decomposition that almost never gets quoted.

By behaviour:

Read that table slowly, because it overturns the usual story. Marketed tax avoidance, the thing this site largely exists to explain, is the smallest line at 1%, about £0.7 billion. Add the "legal interpretation" gap, the lawful-but-contested arrangements, and you reach about £5.6 billion of contested-but-legal planning. The clearly illegal part, evasion plus criminal attacks, is about £10.8 billion combined. The single largest behaviour is just people getting it wrong: failure to take reasonable care, at 31%.

By tax type, the corporate share leaps out:

• Corporation Tax: 15.8% gap, about £18.6 billion, fully 40% of the entire UK tax gap, and the single largest component. Crucially, HMRC attributes this overwhelmingly to small-business non-compliance, not to multinational structures.
• Income Tax, National Insurance and Capital Gains together: 3.0% gap, about £14.4 billion, 31% of the total.
• VAT: 5.0% gap, about £8.9 billion, 19% of the total.
• Excise duty: 5.8% gap, about £3.1 billion.

And by who is responsible:

• Small businesses: 60% of the entire gap, up from 48% in 2019-20.
• Large businesses: 12%, down from 15%.
• Mid-sized businesses: 9%.
• Criminals: 9%.
• Individuals and wealthy individuals together: about 10%.

This is the figure to sit with. Small businesses are 60% of the UK tax gap and rising, while large businesses are 12% and falling. That does not mean small firms are the villains; HMRC's own behaviour split shows most of it is carelessness and error, not fraud. It means the system is hardest to comply with for the people least equipped to comply, and the famous corporate avoidance the headlines obsess over is, as officially measured, a single percentage point. The big structures are real. They are just mostly counted in a different ledger, because a structure that complies with the letter of the law does not register as a "gap" at all.

United States: $696 billion gross, $606 billion net

The IRS projects a gross tax gap of about US$696 billion for tax year 2022, with a voluntary compliance rate of 85.0%. This is a projection rather than a final audited estimate, and the IRS has said it will update it. After late payments and enforcement, the net gap is about US$606 billion. By component:

• Underreporting, tax understated on returns filed on time: US$539 billion, about 77%.
• Underpayment, reported but not paid on time: US$94 billion, about 13%.
• Non-filing: US$63 billion, about 9%.

By tax type:

• Individual income tax: US$514 billion.
• Employment tax: US$127 billion.
• Corporate income tax: US$50 billion.
• Estate tax: US$5 billion.

The dominant driver is individual income underreporting, much of it from pass-through businesses, the self-employed and cash work where no third party reports the income to the IRS. The US does not publish HMRC's avoidance-versus-evasion-versus-error breakdown. And note the caveat that matters most for this site: the US$50 billion corporate line is widely regarded as an undercount, because offshore arrangements and transfer-pricing disputes are not fully captured in the headline number. The corporate structures we describe elsewhere largely live outside this figure, which is precisely why the figure looks so small.

Australia: A$58.2 billion, and the small-business share again

The Australian Taxation Office puts the overall net tax gap at A$58.2 billion, or 9.1%, for 2022-23. By segment:

• Small business income tax: A$27.2 billion, a 17.4% gap, by far the largest component.
• Individuals not in business: A$12.5 billion.
• GST: A$8.1 billion, a gap of about 9.1%, up sharply from 6.4% the year before.
• Large corporate groups: A$3.7 billion.
• High-wealth and medium business: A$2.9 billion.
• Excise: A$1.6 billion.

The ATO separately estimates about A$25 billion was lost to the shadow economy in 2022-23. Like the UK, Australia does not publish a clean avoidance-versus-evasion split, but the pattern is identical: small business is the largest single piece, and large corporates, at A$3.7 billion, are a fraction of it.

Canada: the new 2014-2022 report

Canada's figure has just been updated, and the update matters, because for years the story was that Canada had only ever produced one tax-gap report and never refreshed it. That is no longer true. The Canada Revenue Agency has now published an "Overall Federal Tax Gap Report" covering tax years 2014 to 2022, superseding the original 2022 report that covered 2014-2018. The current headline figures, for 2022:

• Gross federal tax gap: 16.0%, or C$59.5 billion.
• Net federal tax gap, after CRA compliance and collection: 9.3%, or C$34.7 billion.
• Reporting non-compliance accounts for about 72% of the gross gap.

The earlier numbers often still quoted, a gross gap of C$35.1 to C$40.4 billion and a net gap of C$18.1 to C$23.4 billion, are the 2018 figures and are now out of date as the current measure. We flag this because the old "Canada's first-ever, never-updated tax gap" framing is widely repeated and is no longer accurate. As with the others, the largest reporting component is the underground economy, undeclared cash income, with offshore non-compliance a prioritised but smaller enforcement target.

India: no formal gap, but a detected-evasion series

India does not publish a tax gap in the HMRC or ATO sense. What it publishes is detected evasion, which is a different and narrower thing: not an estimate of everything missed, but a record of what enforcement actually caught. For the 2024 financial year that was ₹2.01 lakh crore (about US$24 billion) of GST evasion across 6,084 cases, nearly double the previous year. We cover the method, dominated by fake Input Tax Credit, on the VAT and GST fraud page. The honest caveat: a detected-evasion figure tells you what was found, not what was missed, so it cannot be compared like-for-like with the estimated gaps above.

What the tax gap proves, and what it does not

Pull the six countries together and a consistent shape appears, and it is not the one most people expect.

• The gap is mostly not corporate avoidance. In the UK, marketed avoidance is 1% of it. The famous structures comply with the letter of the law and therefore mostly do not show up in a "gap" at all.
• The gap is mostly error and small-business non-compliance. Small businesses are 60% of the UK gap and the single largest segment in Australia, and most of it is carelessness, not crime.
• The gap is partly contested-but-legal (the UK's 12% "legal interpretation") and partly clear crime (evasion, carousel fraud, fake invoices), and these are different things that should never be added together and called one number.

So when a politician says "we will close the tax gap," ask which part. Closing the error component means helping small firms comply. Closing the criminal component means resourcing fraud enforcement. Neither touches the lawful corporate avoidance this site is mostly about, because that avoidance is, by design, not in the gap. That is not a comforting conclusion. It is the accurate one, and it points the finger exactly where the rest of this site does: at rules that are lawful and unfair, not at a number that measures something else.