The short version
- The tax numbers genuinely do differ: a sole trader pays Income Tax and Class 4 National Insurance on profit directly; a limited company pays Corporation Tax first, then dividend tax on anything actually drawn out afterwards.
- At the profit levels most genuinely small shops are actually at, the tax difference between the two is usually small - the structures start to diverge meaningfully at higher, sustained profit, not at the level most new shops begin at.
- A limited company brings real extra admin regardless of profit level: Companies House filings, separate statutory accounts, more formal bookkeeping - genuine ongoing costs, not a one-off decision.
- Limited liability is a genuine, separate reason to incorporate, entirely apart from the tax question - worth weighing on its own terms, not folded into a single "which is cheaper" comparison.
- The actual, honest question is not "which pays less tax" but "does the added cost and complexity buy this specific shop something it genuinely needs right now" - a different question, with a different answer at different stages of the same business.
The tax numbers, stated plainly
Checked 27 September 2026: a sole trader pays Income Tax on business profit directly, at the same rates as any other personal income, plus Class 4 National Insurance through Self Assessment - one tax return, one set of figures, profit taxed once. A limited company pays Corporation Tax on its profit first - the government's own current Corporation Tax rates page confirms 19% on profit up to £50,000, 25% above £250,000, with Marginal Relief tapering the rate between the two - and then, separately, anything actually paid out to the owner as a dividend is taxed again, after a dividend allowance. Profit left inside the company, not drawn out, is only taxed once, at the Corporation Tax rate - the detail that makes the comparison genuinely dependent on how much a specific owner actually needs to take out to live on.
The specific rates behind the comparison, as they stand today
The government's own guidance on dividend tax confirms the current dividend allowance is £500 a year, with dividend income above that taxed at 10.75% in the basic rate band, 35.75% in the higher rate band, and 39.35% in the additional rate band for the 2026 to 2027 tax year. On the sole trader side, the government's own page on self-employed National Insurance rates confirms Class 4 contributions for 2026 to 2027 are charged at 6% on profits between £12,570 and £50,270, and 2% above that threshold, on top of ordinary Income Tax at the usual personal rates. These are the real, current numbers behind the comparison - worth checking directly against the live gov.uk pages before relying on them for an actual decision, since all four figures are reviewed and can change at the start of a new tax year.
Why this usually matters less than the headline comparison suggests
For a shop at an early, modest profit level, the two structures usually land close enough together that the tax difference alone rarely justifies the switch on its own. The comparison genuinely starts to favour a limited company more clearly at higher, sustained profit - specifically when profit consistently exceeds what an owner needs to draw out to live on, letting some of it stay taxed once inside the company rather than being drawn out and taxed twice. Reaching for a limited company at a profit level well below that point is optimising for a tax advantage that has not actually arrived yet.
A real worked comparison, using today's actual rates
Take a shop with £30,000 of profit for the year, with the owner drawing out everything the business makes to live on, and no other income. As a sole trader: Income Tax and Class 4 National Insurance are both charged on the full £30,000 of profit directly, under ordinary Self Assessment rules. As a limited company: Corporation Tax at 19% is charged on the £30,000 first, leaving roughly £24,300 available to distribute; drawing that out as dividends means paying no tax on the first £500 under the dividend allowance, and 10.75% on the rest within the basic rate band. Run through both routes honestly, the limited company route in this specific example does not produce a dramatically lower total tax bill than the sole trader route - the double layer of Corporation Tax followed by dividend tax closes most of the gap that the headline 19% Corporation Tax rate, looked at alone, makes the company route look like it should produce. This is exactly the "usually matters less than it looks" point above, made concrete with today's real numbers rather than left as an abstract claim - the two routes are close enough at this profit level that the extra admin of a limited company is being bought for a genuinely small tax difference, not the large one the headline rates alone might suggest.
The cost side of the ledger, which the tax comparison alone leaves out
A limited company carries genuine ongoing admin a sole trader does not: annual accounts filed with Companies House, a confirmation statement, generally more involved bookkeeping, and often the cost of an accountant to do some or all of it properly rather than risk getting it wrong. None of this is a reason to avoid incorporating - plenty of genuinely small businesses are limited companies for good reason - but it is a real, recurring cost that a pure tax-rate comparison leaves out entirely, and it applies at every profit level, not only once the business is large.
The separate reason that has nothing to do with tax at all
Limited liability - the legal separation between a company's debts and an individual owner's personal assets - is a genuine, freestanding reason to incorporate, independent of anything about tax efficiency. A sole trader is personally liable for the business's debts in a way a limited company's owner generally is not, and for some sellers, particularly ones carrying real financial risk in their supply chain, that protection is worth having regardless of what the tax comparison says. Folding this into a single "which is cheaper" question misses that it is answering a genuinely different concern.
What actually setting one up costs and takes, in practice
The government's own guide to registering a company confirms the direct registration cost is £100, paid by debit or credit card, with the company usually registered within 24 hours - a genuinely small, fast, mechanical step on its own. The real ongoing cost is not this one-off fee; it is the recurring admin already described above, repeated every single year the company exists, which is worth weighing far more heavily than the trivial setup cost when deciding whether the switch is actually worth making. A seller who has looked only at the £100 registration fee and concluded incorporating is cheap has missed the part of the cost that matters most over time.
Why VAT sits outside this decision entirely
It is worth being clear that VAT registration is a separate question, governed by the same turnover threshold regardless of which structure is chosen - a sole trader and a limited company both have to register once taxable turnover crosses the same figure, and neither structure delays or accelerates that requirement. This is worth stating plainly because it is a common point of confusion: incorporating does not change when VAT registration becomes compulsory, and a shop weighing this decision should not expect the switch to have any bearing on that separate, independent threshold.
Why switching later is entirely normal, not a sign of getting it wrong the first time
Starting as a sole trader and incorporating later, once profit has genuinely grown past the point where the numbers start to favour it, is a completely ordinary path rather than evidence the original choice was a mistake - the honest right answer for a specific shop changes as that shop's own profit and risk genuinely change, and a decision made sensibly for a small, early-stage shop is not the same decision that stays right forever. The practical process of incorporating an existing sole trader business partway through is well established and something an accountant handles routinely, including transferring existing stock and any outstanding orders into the new company structure cleanly - worth knowing this is a real, manageable step, not a reason to over-plan for a later stage of growth before the business has actually reached it.
The question actually worth asking
Put plainly: does becoming a limited company buy this specific shop, at its actual current profit level and actual current risk exposure, something it genuinely needs right now - meaningful tax efficiency at real, sustained profit, or liability protection against a real risk - or does it mainly add admin and cost to a shop that does not yet have either problem. The honest answer changes as a shop grows, which is exactly why this is worth revisiting deliberately at a later, larger stage rather than being treated as a single decision made once and never looked at again.
A worked example
A shop with modest profit, run alongside other income, where the owner draws out essentially everything the business makes to live on: the tax difference between the two structures is genuinely small here, as the worked comparison above shows directly, and the limited company's extra admin is a real cost bought for very little tax benefit. The same shop years later, profit consistently well above what the owner actually needs to draw out to live on, some of it genuinely left inside the business to reinvest in stock: the calculation looks meaningfully different, and revisiting the decision properly, ideally with an accountant who can run the actual numbers, becomes genuinely worthwhile rather than premature.
Where this stays worth an accountant's own input
Sellhelm's own Finances page keeps the real profit figure this decision actually needs to be based on - not a guess, not a hoped-for number - but the sole trader versus limited company decision itself depends on genuinely personal facts an accountant is better placed to work through properly: other income, risk appetite, and what a specific owner actually needs to draw out to live on.
Questions people ask
Is a limited company always more tax-efficient than a sole trader?
No. At modest profit levels the tax difference is usually small, and a limited company’s extra admin can outweigh the benefit. The advantage grows clearer at higher, sustained profit, especially profit left inside the company rather than drawn out.
What is the actual Corporation Tax rate for a small company?
19% on profits up to £50,000, 25% above £250,000, with marginal relief tapering the rate between those two figures.
Does a limited company protect my personal assets?
Generally yes - limited liability separates a company’s debts from an individual owner’s personal assets, a genuine reason to incorporate that is entirely separate from any tax consideration.
What is the real question to ask before switching from sole trader to limited company?
Not "which pays less tax," but whether the extra admin and cost of a limited company buys this specific shop something it genuinely needs right now - real tax efficiency at its actual profit level, or liability protection against a real risk.