CIS invoice software, explained

The manual process — and where it goes wrong

If you run CIS for one or more contractors, the monthly grind is familiar. For every subcontractor invoice you receive, you have to:

• Read the invoice and separate the labour from the materials (the deduction never touches materials).
• Check the subcontractor's verification status to know whether the rate is 20%, 30% or 0%.
• Calculate the deduction on the labour only, and the net amount to pay.
• Re-key all of it into Xero, QuickBooks or a spreadsheet — UTR, verification number, the split, the deduction.
• Pull the totals together for the CIS300 monthly return before the 19th.

It's slow, and it's repetitive, and that's exactly the kind of work where a tired hand makes a costly slip — deducting on materials by mistake, applying 20% to an unverified subcontractor, or transposing a figure on the way into the ledger. Multiply that across a practice with several contractor clients and the manual route quietly eats hours every month.

What CIS invoice software actually does

Good CIS invoice software reads a subcontractor's invoice and does the mechanical CIS work for you: it identifies the labour and materials lines, applies the correct deduction rate, and calculates the deduction and net pay. Instead of typing, you review.

The better tools then connect to your accounting software, so the approved figures land in the right place without a second round of re-keying, and they roll up the monthly totals you need for the return. The goal is simple: turn a stack of invoices into clean, checked CIS bills with far less manual effort — and far less room for the errors manual entry invites.

What to look for in a CIS tool

Not every tool that mentions CIS does the part that actually hurts. When you're comparing options, weigh these:

1. It splits labour from materials

This is the heart of CIS, and the most common source of error. The deduction applies to labour only— materials, VAT and qualifying plant are exempt. A tool that doesn't pull out the split isn't saving you the hard part. (If you want the rule in full, see the CIS deductions guide.)

2. It handles all three rates correctly

20% for registered and verified subcontractors, 30% for unverified, and 0% for gross-payment status. The tool should make the rate explicit per subcontractor so you can confirm it against what HMRC told you at verification.

3. It exports where your books live

Native Xero write-back or clean CSVmatters — otherwise you've only moved the re-keying one step downstream. The win is eliminating manual entry end to end.

4. It keeps you in control

You should review and approve every figure before anything posts. Automation that files silently is a liability; automation that drafts and waits for your sign-off is leverage. You remain responsible for what reaches HMRC.

5. It feeds the CIS300

The point of all this is the monthly return. A useful tool gives you the labour, materials and deduction totals you need for the CIS300, due by the 19th — see how to file a CIS return.

How CISflow does it

CISflow is built around the parts above. You forward a subcontractor invoice and it reads the document — PDF, scan or photo — and extracts the CIS fields: UTR, verification number, the labour/materials split, the deduction rate, the deduction amount and the net pay.

Those figures are laid out for you to review and approve. Nothing is silent and nothing is automatic without your sign-off. On approval, CISflow writes a clean, HMRC-ready CIS bill straight into Xero (or exports CSV for QuickBooks, Sage and others) and gives you the totals for your CIS300. You stop typing; you keep control.

Want to see the numbers first? Use the free CIS deduction calculator — enter labour, materials and the rate, and it returns the deduction, net pay and the CIS300 figures, no sign-up needed.

Is it worth automating?

If you process more than a handful of subcontractor invoices a month, the answer is usually yes — not because the maths is hard, but because the volume and the repetition are where time and accuracy leak away. Pricing on CISflow is £39/mo Solo or £99/mo Practice, with a 14-day free trial and no card to start, so you can put your own invoices through it before deciding.

CISflow is live and in early access. Start free to try it on a real invoice today.

This guide is general information on UK CIS, not tax advice. CISflow is a data-entry tool, not an accountancy or tax service — you remain responsible for figures submitted to HMRC, and should always verify a subcontractor's status and rate with HMRC.