Tools DownComing soon on the App Store

The AI for buildersCIS on the contractor’s invoice. Not on the homeowner’s.

Mark a customer as a CIS contractor once, and it remembers. Their invoices carry the CIS deduction on the labour and, if you’re both VAT registered, the reverse-charge wording. The homeowner’s invoice for the same week looks like a homeowner’s.

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iPhone. First month free, no card.

You: Invoice Harris Construction for the Jones extension. Labour £3,200, materials £800.

Tools Down: Done. Harris pays £3,360 after CIS.

InvoiceDraft

Jones extension

Harris Construction Ltd

Labour
£3,200
Materials
£800
VAT (20%) — reverse charge, not charged
£800
CIS deduction (20% of labour)
−£640

Amount due£3,360

  • Reverse charge: VAT Act 1994 Section 55A applies
  • CIS deduction of 20% is taken from the labour on this invoice.
  • Due in 30 days
ShareMark paid
The wording as it prints on the invoice. Business customers get 30 days to pay, or 14 if you set it.

Heard on the forums

Getting the subbie work and doing the subbie work is the easiest bit. Getting paid is often the hardest part.

A tradesman on DIYnot, August 2026

Same week, a householder

You don’t switch anything. The customer does.

Mrs Morgan is a householder, so her invoice carries VAT and no CIS, and it’s due on receipt. How you’ve marked each customer decides what their invoice carries.

InvoiceDraft

Morgan extension

Mr and Mrs Morgan

Extension, as quoted
£6,000
VAT (20%)
£1,200

Amount due£7,200

  • Due on receipt
  • The CIS deduction follows your CIS status: 20% registered, 30% unregistered, none with gross payment status.
  • The reverse charge applies only when you’re VAT registered and the customer is a VAT-registered CIS contractor.
  • Extras on a contractor’s job count as labour for CIS, unless they’re materials.
  • Business customers get 30 days to pay, or 14 if you set it; householders are due on receipt.

What matters on your jobs

What it does on a build

A deposit, the stages, then the balance

You say: Invoice the Morgans 40% now the walls are up.

A deposit to book, then each stage as a percentage of the quote or an amount, with what’s left to bill shown. The final invoice takes every one off, “Less Stage 1 (INV-0003)”, and asks for the balance.

Variations on the record the day they’re agreed

You say: Morgans want the doorway moved, £450, agreed today.

Saved on the job at that price, the day it’s agreed, and on the final invoice as an extra. When “you said it would be X” comes up, the record is there.

Photos before it’s covered up

You say: Show me the footings at the Morgans’.

Footings, the steel, the DPC, the cavity: filed on the job as you take them, for building control and for the conversation that comes later.

The numbers your accountant asks for

You say: Export everything.

A ZIP of CSV files, with the CIS deduction on each invoice, plus the PDFs, photos and chats. Expenses also export as a CSV in Xero’s or FreeAgent’s layout, or plain for QuickBooks and Sage.

Price and the free plan

Made for one. Priced for one.

£29.99 a month including VAT, or £24.99 if you reclaim VAT. One person, no minimum, no setup fee, no training.

  • Your first month is free, with no card.
  • After that you’re on the Free plan: 50 messages a month to Tools Down, and every screen keeps working.
  • Tools Down Pro is paid monthly through Apple. It lifts the message limit.
  • Fair use applies on every plan, with limits set far above what one person books or asks for in a month.
What counts as a message, and how cancelling works

Tools Down for iPhone

Coming soon on the App Store

First month free, no card.

Straight answers

Questions builders ask

Can I send CIS invoices?

Yes. Mark a customer as a CIS contractor and their invoices carry the CIS deduction on the labour, extras included unless they’re materials; a householder’s don’t, because householders are outside CIS (HMRC: CIS 340).

Can I invoice a build in stages?

Yes. Invoice each stage as a percentage of the quote or an amount, and you see what’s left to bill. The final invoice takes any deposit and every stage off and asks for the balance.

What does CIS take off my invoice?

A registered subcontractor has 20% deducted, an unregistered one 30%, and gross status none; there’s no deduction on VAT or on materials you paid for directly (GOV.UK: what you must do as a CIS subcontractor).

When does the domestic reverse charge apply?

Between VAT-registered businesses for construction services reported under CIS, unless the customer is an end user; never to a private householder (GOV.UK: VAT domestic reverse charge).

Can I charge interest when a contractor pays late?

On business-to-business debts, statutory interest is 8% plus base rate, with a fixed £40 to £100 recovery charge (GOV.UK: late commercial payments).

Can the main contractor pay me only when they get paid?

On a construction contract, a “pay when paid” clause is ineffective unless the payer’s payer is insolvent (s113). A contract with a homeowner who lives there is outside those rules (s106).

How do I get my CIS numbers to my accountant?

Export everything: your invoices come out as a CSV with the CIS deduction on each, alongside the PDFs. Expenses export as a CSV too.

Paperwork and rules

CIS, the reverse charge and the rest

Information, not advice. Open a rule to read it, with its source; check the source for your own job.

Your work

The jobs you price

  • Single-storey and side-return extensions
  • Knock-throughs with steels
  • Garage conversions and remodelling
  • Renovations, managing the other trades
  • Brickwork, repointing, chimneys and lintels
  • Garden walls, patios and paths
  • Subbing for a main contractor, on day rate or price work

How the money comes in

  • Homeowners: a deposit, stage payments, then a final invoice that gets queried.
  • Main contractors: CIS deducted, paid on their pay run.
  • Variations that start as “while you’re here”.
  • Retentions held back at the end.

Keep looking

Free guides and templates

Other trades, and how it compares