CIS Deductions Tracker for UK Subcontractors: How CIS Works and What to Record
If you work in construction as a self-employed subcontractor, the Construction Industry Scheme (CIS) affects almost every payment you receive. Money is taken off before it reaches your bank account, and it is up to you to keep track of it so you can claim it back. This guide explains how CIS works in plain English and how a simple CIS deductions tracker keeps your records straight for Self Assessment.
What is the Construction Industry Scheme?
Under CIS, contractors deduct money from a subcontractor's payments and pass it to HMRC. These deductions count as advance payments towards the subcontractor's tax and National Insurance. CIS covers most construction work in the UK, including building, alterations, repairs, decorating, demolition and site preparation.
The scheme is not optional for contractors, but subcontractors do not have to register. Registering does make a big difference to how much is deducted.
CIS deduction rates: 20%, 30% or 0%
- 20% if you are registered for CIS
- 30% if you are not registered
- 0% if HMRC has given you gross payment status, which has extra conditions about your turnover and tax record
Deductions are only taken from the labour part of a payment. The contractor should not deduct CIS from the cost of materials you have bought for the job, from VAT, or from equipment hire directly related to the job. If your invoices show materials separately, check your statements to make sure the deduction has been worked out on the right amount.
Payment and deduction statements
Each tax month (which runs from the 6th of one month to the 5th of the next), a contractor who has paid you must give you a payment and deduction statement. They must give it to you within 14 days of the end of the tax month. It shows the gross amount paid, the cost of any materials, and the amount deducted.
Keep every one of these statements. They are your proof of the tax already paid on your behalf. If a statement is missing or looks wrong, ask the contractor for it straight away, as it is much harder to sort out months later.
Claiming CIS deductions back at Self Assessment
If you are a sole trader or in a partnership, you claim your CIS deductions through your Self Assessment tax return. You enter your total income and your total CIS deductions for the tax year (6 April to 5 April). HMRC takes the deductions off your tax and Class 4 National Insurance bill. If more has been deducted than you owe, which is common once allowable expenses are taken into account, you get a refund.
Limited companies work differently: they claim back CIS deductions through their payroll (the Employer Payment Summary) rather than through Self Assessment.
The online Self Assessment deadline is 31 January after the end of the tax year. You can file as soon as the tax year ends on 5 April, and filing early means any refund arrives sooner.
What a CIS deductions tracker should record
A tracker brings everything together in one place so your year-end totals are quick to add up. For each payment, note:
- the contractor's name
- the date paid and the tax month it falls in
- the gross amount, the materials amount and the amount liable to deduction
- the CIS deducted
- the net amount received
- whether you have received the payment and deduction statement
Alongside this, log your business expenses by category (tools, materials you paid for, van costs, phone, protective clothing) and your business mileage. Those expenses reduce your taxable profit, which is often what turns your CIS deductions into a refund.
How long to keep your records
If you are self-employed, HMRC says you should keep your records for at least 5 years after the 31 January Self Assessment deadline for the tax year they relate to. That includes payment and deduction statements, invoices, receipts and bank statements.
Keeping it simple
A few minutes each month, when the statements arrive, saves hours in January. Tick off each statement, add up the month and keep your receipts with it.
Pennaby's CIS Subcontractor Expense & Income Tracker 2027/28 is a printed record book built around exactly this: monthly CIS statement pages, expenses by category, a mileage log and a tax-year summary for 6 April 2027 to 5 April 2028. Prefer to print at home? Our Monthly Budget Tracker (UK, £) includes income and expense log pages you can use alongside your statements.
This guide is general information, not tax advice. For your own situation, check GOV.UK or speak to an accountant.