Self-employed tax
Estimate Income Tax and NI on your self-employed profit.
Open calculatorFull expensing, the Annual Investment Allowance or writing down allowances — which you get depends on what you are buying and who is buying it. Talk to Buzz before a large purchase.

Enter the details, then click Calculate to see which relief applies.
When you buy equipment for a business you usually cannot deduct the cost like a normal expense. You claim capital allowances instead, and which one you get changes the timing enormously — sometimes all of it this year, sometimes a fraction a year for a decade.
Full expensing. A 100% first-year allowance on new main-rate plant and machinery, and 50% on new special-rate assets. Uncapped, and permanent. Two conditions people miss: it is for companies only, and the asset must be new and unused.
The Annual Investment Allowance still matters. The AIA gives 100% relief on up to £1,000,000 a year, covers both pools, and — unlike full expensing — is available to sole traders and partnerships and to second-hand assets. For most small businesses it does everything full expensing would have done.
Where the money gets stuck. Special rate assets. A fit-out's lighting, wiring, heating and air conditioning are integral features, and once the AIA is used up they attract 6% a year, which takes decades to relieve. Pointing the AIA at special-rate spend first, and leaving main-pool spend to full expensing, is usually the better order.
The main pool writing down allowance also fell from 18% to 14% in April 2026, which makes getting the up-front allowances right worth more than it used to be.
Divide the gross figure by 1.20 for standard-rate VAT. £120 ÷ 1.20 = £100 net, so the VAT is £20. Taking 20% off £120 gives £96, which is wrong, and it is the most common VAT mistake in small business bookkeeping — it understates net sales and overstates the VAT by a few percent every time. For the reduced 5% rate, divide by 1.05. A useful shortcut for standard rate: the VAT in a gross figure is one sixth of it.
When your VAT-taxable turnover exceeds £90,000 in any rolling twelve-month period, or when you expect to exceed it within the next thirty days alone. The rolling test is the one that catches people: it is not your accounting year and not the calendar year, so you have to check it monthly. Registering late means HMRC can charge you the VAT you should have collected from the date you crossed the threshold — money you never took from your customers and generally cannot go back and ask for. Watch it every month.
It depends entirely on who your customers are. If they are mainly VAT-registered businesses, they reclaim the VAT anyway, so registering costs them nothing and lets you recover VAT on your own purchases and overheads — often worth several thousand pounds a year. If you sell to consumers or small unregistered businesses, registration effectively makes you 20% more expensive or cuts your margin by that much, and it is usually a poor idea. There is also the admin: quarterly returns, digital records and MTD obligations from day one.
A simplified scheme for businesses with turnover up to £150,000 excluding VAT, where you pay HMRC a fixed percentage of your gross turnover instead of tracking VAT on every purchase, and generally cannot reclaim input VAT except on capital assets over £2,000. It suits low-cost service businesses and penalises anyone who buys a lot. The limited cost trader rule pushes businesses spending little on goods onto a 16.5% rate, which removes most of the benefit. Run it both ways on your actual figures before joining — it is not a one-way saving.
It depends on what you sell, whether it is goods or services, whether the customer is a business or a consumer, and where they are. The general rule for business-to-business services is that the place of supply is where the customer belongs, so UK VAT is not charged and the reverse charge applies — but there are numerous exceptions, and digital services to consumers follow different rules again. Goods bring customs and, for Northern Ireland, the Windsor Framework. Getting it wrong is expensive to unwind, so check before assuming.
Correct it. Errors below the reporting threshold and not deliberate can usually be adjusted on your next return; larger or deliberate errors must be notified to HMRC separately on form VAT652. Unprompted disclosure attracts substantially lower penalties than an error HMRC finds itself, so the incentive is firmly on telling them first. Late returns and payments now work on a points-based system with separate late payment penalties and interest. The practical lesson is that a VAT mistake found and reported is a small problem, and the same mistake discovered in an inspection is not.
Estimate Income Tax and NI on your self-employed profit.
Open calculatorCompare ways to take money out of your limited company.
Open calculatorIR35, capital gains, stamp duty and more.
Browse allStart with a single sale. You quote £1,000 for a job, exclusive of VAT.
Reverse it and the trap appears. If a customer agrees £1,200 including VAT, the net is £1,200 ÷ 1.20 = £1,000 and the VAT is £200. Taking 20% off £1,200 gives £960, which is £40 wrong on every invoice.
Now scale it to a quarter. A business invoices £42,000 net over three months and spends £12,900 including VAT on standard-rated costs.
Dividing a VAT-inclusive figure by 6 is the quick way to find the VAT inside it at 20%, which is worth remembering when you are checking a supplier invoice.
Late VAT returns now attract points rather than an automatic penalty, but the points accumulate and turn into a fine, and late payment carries interest separately. Our article on the real cost of late VAT returns covers how that works.








