What expenses can CIS subcontractors claim?
Claiming the right expenses is what turns a CIS deduction into a refund. Here's what subcontractors can usually claim, with the simple test for whether a cost counts.
Khurram Nisar
Founder and editor, CalcFree
Builds and maintains CalcFree's calculators; reviews every tool against official HMRC, CRA and ATO guidance before publication.
I started CalcFree because most online calculators either hide their workings or quietly use out-of-date figures, and neither is much help when you’re trying to make a real decision about money. My background is in building websites and tools at Techithrive, and that practical, “show me how it actually works” mindset runs through everything here.
What I do on CalcFree
I build the calculators, write the explanations that sit alongside them, and keep the underlying figures current. Every tool is something I’d be comfortable using myself to plan a decision — which is the bar I hold them to.
How I review a calculator
Before a tool is published, I check the calculation logic against the relevant official source — HMRC for UK tax, the CRA for Canada, the ATO for Australia — and run it through worked examples to confirm the numbers behave sensibly at the edges as well as the middle. I write the assumptions down in plain English on the page, because a calculator you can’t interrogate isn’t trustworthy.
How content is reviewed
The written guidance is there to explain the result, not to pad the page for search engines. I aim for plain language, real examples, and honest limitations — including saying clearly when something needs an accountant rather than a calculator.
How figures are kept up to date
Tax bands, thresholds and prices live in editable data files, separate from the code, and are reviewed each tax year or when rules change. Every tool shows a visible “last reviewed” date so you can see how current it is. If a figure is wrong, I’d rather hear about it and fix it quickly than pretend the site is infallible — see the Sources and Methodology pages for how that works.
Tools by Khurram Nisar
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 calculatorConcrete & Gravel Calculator
Running short mid-pour is every DIYer's nightmare. Enter your slab dimensions to get the volume in cubic yards, the number of bags, and a rough cost — with a waste allowance built in.
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 calculatorFence Cost Calculator
Before you ring a contractor or load up the trolley, get a grounded estimate. Enter your fence length and material to see the posts and concrete you'll need, the material cost, and an installed price range.
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 calculatorArticles by Khurram Nisar
CIS deductions explained in plain English
If a contractor takes a chunk off your pay before you see it, that's CIS. Here's what the deduction is, why it happens, and why most subcontractors get some of it back.
Company car tax explained: EV vs petrol BIK
A company car is a taxable perk, and the tax gap between an electric car and a petrol one is enormous. Here's how benefit-in-kind works and why EVs win.
IR35 explained for contractors
IR35 sounds complicated, but the core idea is simple: are you genuinely in business for yourself, or working like an employee? Here's what that means for your pay.
Do I need to tell HMRC about my side hustle?
Selling online or freelancing on the side? Here's the simple rule for when HMRC needs to know, and how the £1,000 trading allowance keeps small earnings tax-free.
Umbrella vs limited company: which keeps more of your money?
Two contractors on the same day rate can take home very different amounts. Here's how umbrella and limited-company pay actually differ, and when each one makes sense.