Construction Industry Scheme

CIS sorted from your phone - verify, deduct and file the CIS300

Built for the people doing the work, not their accountant. Verify subcontractors, work out the right deduction and file your monthly CIS return online to HMRC - on site, in the van, or back at the yard.

CIS Return Tax month to 5 May 2026 A. Mason Verified · 20% £1,800 −£360 T. Rivett Verified · 20% £950 −£190 K. Doyle Verified · 30% £600 −£180 Total deducted £730 File to HMRC Due by the 19th

No more fiddly spreadsheets. No more logging into the HMRC portal. No more guessing the right rate. TradeKit handles the whole Construction Industry Scheme - verification, deductions, statements and the monthly return - in the same app as your quotes and invoices.

19th

Never miss the deadline

Your CIS300 is due by the 19th of every month. Miss it by a single day and HMRC charges an automatic £100 penalty - even on a nil return. TradeKit gets the return ready so you can file in minutes.

What you get

Everything you need for CIS

The full scheme, handled - for contractors who pay subcontractors.

Subcontractor verification

Check a subcontractor with HMRC and get the right tax treatment back - gross, the standard rate, or the higher unmatched rate - so you deduct correctly every time.

The right deduction, automatically

TradeKit applies the deduction to labour only and leaves materials out of it, so every payment to a subcontractor is worked out the way HMRC expects.

CIS300 monthly return

Build and file your CIS300 online to HMRC, with the declarations handled for you. Nil returns and periods of inactivity are covered too.

Deduction statements

Produce the payment and deduction statements your subcontractors need to claim their tax back - ready to share as a PDF.

Records & audit trail

Every submission is stored with a confirmation step and a tamper-evident audit trail, so you always have proof of what was filed and when.

One app, not two

CIS lives alongside your quotes, invoices, expenses and mileage - no separate payroll software, no second subscription, no spreadsheets.

How it works

Four steps, start to filed

The same order you already work in - verify, pay, review, file.

1

Verify your subcontractors

Add a subcontractor and verify them with HMRC to confirm the deduction rate that applies to them.

2

Record payments as you go

Enter what you pay. TradeKit splits labour and materials and works out the CIS deduction for you.

3

Review the monthly return

At the end of the tax month, TradeKit pulls your records into the CIS300 ready for you to check.

4

Confirm and file to HMRC

Confirm the declarations and file online. Your subcontractors get their deduction statements.

CIS questions, answered

The basics, in plain English

The things people ask before they trust software with a return.

What is a CIS300 monthly return?

If you pay subcontractors for construction work, you’re a contractor under the Construction Industry Scheme and you must send HMRC a monthly return - the CIS300 - listing what you paid each subcontractor and the tax you deducted. TradeKit builds it from your records and files it for you.

When do I have to file, and what if I’m late?

CIS returns are due by the 19th of each month, covering the tax month that ended on the 5th. If you miss the deadline HMRC charges an automatic £100 penalty straight away, rising to £200 after two months - so it pays to file on time, even when it’s a nil return.

What’s the difference between 20% and 30%?

When you verify a subcontractor, HMRC tells you the rate to deduct: 0% (gross) for those with gross payment status, 20% for registered subcontractors, and 30% if they aren’t registered or can’t be matched. TradeKit applies the right rate automatically once a subcontractor is verified.

What is a payment and deduction statement?

It’s the record you must give each subcontractor showing what you paid them and what you deducted. They use it to claim the deduction back against their own tax bill. TradeKit generates these as PDFs you can send straight on.

Do I need separate CIS software?

No. TradeKit handles CIS alongside your quotes, invoices, expenses and mileage, so you’re not juggling - or paying for - a second app just to stay on top of the scheme.

Built to HMRC’s CIS Online specification

TradeKit’s CIS submissions are built against HMRC’s published CIS Online specification for contractors, including the IRmark signing and validation the service requires. TradeKit is developed by KIH Technologies Ltd, a UK-registered software company.

Subcontractor verification and CIS300 filing are built and HMRC-tested, and go live on production credentials. Everything else on this page is available today.

Ready when you are

Take the headache out of CIS

Start your 30-day free trial - have a proper look around before you commit.

TradeKit is a software tool that helps you prepare and file your own Construction Industry Scheme returns. It does not provide tax or accountancy advice. You remain responsible for the accuracy of the information you submit to HMRC. TradeKit™ is a trade mark of KIH Technologies Ltd (UK trade mark application UK00004386242).