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.
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Most online calculators hand you a number with no idea what it assumed or whether the figures are current. CalcFree does the opposite: every tool states its assumptions in plain English, links the official source, shows when it was last reviewed, and says clearly where an estimate ends and professional advice should begin.
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UK Contractor & Tax Tools
Calculators for UK contractors, subcontractors and the self-employed — CIS refunds, umbrella vs limited company, side-hustle tax and company car tax.
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Home Project Cost Tools
Estimate home project costs — fencing, retaining walls, paver patios, concrete and gravel, plus solar payback and EV running costs.
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The tools people reach for most — each one shows its working and cites its source.
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.
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2. See the assumptions
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Calculations run on your device. We don't store the figures you type in.
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Every tool states what it assumes and links the official source — HMRC, CRA, ATO and others.
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Rates and thresholds are reviewed each tax year, with a visible last-updated date.
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How our calculators are built
Calculation logic is written and tested separately from the rates it uses, so the maths can be checked independently and figures can be updated each tax year without touching the code. We test typical values and the awkward edges, and we state every assumption on the page.
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Tools and guidance are written by a named author, reviewed against official sources before publication, and corrected quickly when something's wrong. Advertising keeps the site free but does not influence what our calculators say.
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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.
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.