UK Tax Calculators for
Businesses & the Self-Employed
Nine free calculators covering everything from PAYE take-home pay to P11D company car tax, MTD ITSA deadlines, and sole trader vs limited company comparisons. Built on current HMRC rates.
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BUSINESS & EMPLOYER
SELF-EMPLOYED & INDIVIDUAL
COMMON QUESTIONS
Should I be a sole trader or limited company?
The right structure depends on your profit level, your attitude to risk, and your plans for the business. As a general rule of thumb, a limited company tends to become more tax efficient once your annual profit exceeds around £30,000 to £35,000, but the numbers alone don't tell the whole story. As a sole trader, all your business profits are taxed as personal income through Self Assessment. You pay Income Tax and Class 4 National Insurance on everything above the Personal Allowance — simple to understand, but the rates climb quickly as your income grows. A limited company is a separate legal entity. You pay Corporation Tax on the company's profits, and as a director you typically draw a small salary combined with dividends, which is generally more tax efficient. The company also offers limited liability, meaning your personal assets are protected if the business runs into financial difficulty. The trade-off is that running a limited company comes with more administrative responsibility — annual accounts, a Confirmation Statement, payroll obligations, and stricter record-keeping. There are also accountancy costs to factor in. Use our Sole Trader vs Limited Company calculator to compare your net take-home under both structures based on your actual expected profit, then get in touch with us for a personalised recommendation.
How is P11D company car tax calculated?
A company car is classed as a Benefit in Kind (BiK) by HMRC, which means it has a taxable value that both the employee and the employer are liable for, even though no cash changes hands. The taxable value is calculated by multiplying the car's P11D list price — the manufacturer's list price including VAT and factory-fitted options — by a BiK percentage. That percentage is set by HMRC based on the car's CO₂ emissions. In 2026/27, petrol and diesel cars range from 17% up to 37%, while fully electric vehicles sit at just 4%, making EVs significantly more tax efficient as a company car choice. The employee pays Income Tax on the resulting taxable value. A basic rate (20%) taxpayer in a £35,000 petrol car at 30% BiK would pay tax on £10,500 of benefit — costing them £2,100 per year. A higher rate (40%) taxpayer would pay £4,200 for the same car. The employer pays Class 1A National Insurance at 15% on the same taxable value, reported annually on a P11D(b) form — or collected in real time if the benefit is payrolled. Use our Company Car P11D calculator to see the exact employee tax cost and employer NI for any car, including a side-by-side comparison with the equivalent electric vehicle.
When do I need to register for MTD ITSA?
Making Tax Digital for Income Tax Self Assessment (MTD ITSA) is HMRC's programme to move self-employed individuals and landlords away from annual Self Assessment tax returns and onto quarterly digital reporting. Mandation is being rolled out in phases based on your total gross qualifying income — that means your revenue before any expenses are deducted, not your profit: From 6 April 2026, MTD ITSA is mandatory if your combined gross self-employment and property income exceeds £50,000 per year. From 6 April 2027, the threshold drops to £30,000, bringing a further wave of sole traders and landlords into the regime. From 6 April 2028, anyone with qualifying income above £20,000 will also be required to comply. Under MTD ITSA you will need to submit four quarterly updates to HMRC each year through compatible software, followed by a Final Declaration that replaces the current Self Assessment tax return. The quarterly deadlines fall on 7 August, 7 November, 7 February, and 7 May. If you are currently below the £20,000 threshold you are not currently required to join, though voluntary sign-up remains an option. Use our MTD ITSA Estimator to check exactly when you become mandated based on your income, and to see your specific quarterly submission deadlines. If you need help getting compliant software in place or want us to handle your quarterly submissions, get in touch with the team.
Evolve Business Assist - Free UK Tax Calculators
Rates current for 2026/27 tax year