UK Contractor & Tax Tools
If you contract, subcontract or run a side business in the UK, your tax is rarely as simple as a payslip. CIS deductions come off before your expenses are counted. Umbrella and limited-company routes leave very different amounts in your pocket. A side hustle can quietly tip you into a higher tax band. The tools in this section are built around those real situations rather than generic sums. Each calculator shows its working, states what it assumes, and links the relevant HMRC guidance so you can check the rules yourself. They give you a clear estimate to plan around — what a CIS refund might come to, whether an umbrella or your own company keeps more of your day rate, how much to set aside on second-income earnings, or what a company car will cost you in tax. None of them is a substitute for advice from an accountant, and every result says so. The aim is simple: help you understand the number before you make a decision about it.
CIS Tax Refund Calculator
If you work under the Construction Industry Scheme, your contractor takes tax off before you're paid — and most subcontractors have paid too much. This works out a rough estimate of what you might be owed.
Open calculatorCompany Car BIK Calculator
A company car is a taxable perk. How much you pay depends on the car's value, its emissions and your own tax band — electric cars are taxed far more lightly than petrol or diesel.
Open calculatorCorporation Tax Calculator
Company profit isn't taxed at a single flat rate. This works out your corporation tax including marginal relief, and shows the effective rate you'll actually pay.
Open calculatorIR35 Take-Home Calculator
An IR35 determination can be worth thousands a year. This compares your estimated take-home pay inside versus outside IR35, so you can see exactly what the decision costs you.
Open calculatorLate Filing & Late Payment Penalty Calculator
Missed the Self Assessment deadline? Penalties stack up the longer you leave it. This estimates what filing and paying late is likely to cost you.
Open calculatorPayment on Account Calculator
That bigger-than-expected January bill is usually payments on account. This works out what you'll owe in January and July, and whether they apply to you in the first place.
Open calculatorSide Hustle Tax Calculator UK
Selling online, freelancing at weekends or doing a bit of tutoring? Here's a rough idea of how much of your side income to keep back for tax.
Open calculatorUmbrella vs Limited Company Calculator
Two contractors on the same day rate can end up with very different take-home pay depending on how they're set up. This compares the two routes side by side.
Open calculatorDividend Tax Calculator
Dividend tax rates went up in April 2026, so a strategy that worked last year might cost you more now. Enter your figures to see what you'll actually pay this tax year.
Open calculatorSalary vs Dividend Calculator
For a single-director company, how should you take money out — all salary, or a small salary plus dividends? Enter the profit you want to extract and see which leaves more in your pocket this tax year.
Open calculator