A&Y CIS Refund Estimator — UK Subcontractors

About

A&Y CIS Refund Estimator helps UK construction subcontractors working under the Construction Industry Scheme estimate their annual tax refund in seconds.

Most subcontractors are owed money back each year. Contractors deduct 20% (or 30% if you are not verified) from your labour payments before you receive them. When you file your Self Assessment, your actual tax bill is usually lower once your personal allowance, materials, allowable expenses and Class 4 National Insurance thresholds are taken into account. The difference is your refund.

This extension does that calculation for you, directly from your browser toolbar.

What it does
• Switch between the 20% (verified) and 30% (unverified) CIS deduction rates
• Enter your gross income, materials, allowable expenses, and any other untaxed income
• See your estimated refund — or any additional tax to pay — instantly
• View a full breakdown: labour income, CIS deducted, taxable profit, Income Tax, Class 4 NI, and total tax bill
• Calculations use 2025/26 UK tax-year figures: personal allowance £12,570, basic rate to £50,270, higher rate to £125,140, allowance tapered above £100,000
• Class 4 NI applied at 6% between £12,570 and £50,270, and 2% above

Who it is for
Self-employed subcontractors registered under CIS who want a quick estimate of their refund position before preparing their Self Assessment return.

Privacy
Everything runs locally in your browser. No accounts, no sign-ups, no tracking. No data is sent to any server, collected, stored or shared.

Disclaimer
This tool provides estimates based on standard UK 2025/26 rates and current CIS rules. It is not a substitute for professional advice or a filed Self Assessment return. For verified figures, please consult a qualified accountant.

About A&Y
A & Y Financial Services is a UK accountancy firm. Visit ayfinancials.com for help with your Self Assessment or to use our free web calculators at ayfinancials.com/tools.