Self-Employed & CIS
CIS Tax Refund Calculator
Because 20% is deducted from all your earnings, most CIS subcontractors overpay tax. Factor in your expenses to see how much HMRC might owe you.
Your Income
Business Expenses
Expenses reduce your taxable profit, which increases your likely refund.
CIS Tax Verdict
Estimated Refund: £2,170.00
Because your contractor already deducted £8,000.00 and your actual tax bill (including NI) is only £5,830.00, HMRC owes you money.
How CIS tax refunds work
If you're a subcontractor in the Construction Industry Scheme (CIS), your contractor deducts money from your payments and passes it to HMRC. For registered workers, this deduction is 20%. For unregistered workers, it's 30%.
These deductions act as advance payments towards your tax and National Insurance bill. However, a flat 20% deduction almost always means you've overpaid tax, because it doesn't take into account:
- Your Personal Allowance: You can earn £12,570 a year completely tax-free.
- Your Business Expenses: Tools, travel, and materials reduce your taxable profit.
Allowable expenses for CIS workers
To maximize your refund legitimately, you should claim all allowable business expenses. The most common ones include:
- Materials and supplies: Anything you buy to complete the job.
- Tools and equipment: Drills, saws, hand tools, and their maintenance.
- Travel and vehicle costs: Fuel, van insurance, repairs, or claiming the flat rate mileage (45p per mile for the first 10,000 miles).
- Clothing: Protective workwear and uniforms (but not everyday clothing).
- Admin: Phone bills, internet, and accountant fees.
How to claim your money back
To get your CIS tax refund, you must complete a Self Assessment tax return after the tax year ends (5 April). You'll declare your total income, your expenses, and the total amount of CIS tax already deducted.
HMRC will calculate your actual tax bill, subtract the CIS deductions you've already paid, and refund the difference directly to your bank account.