Because billing in DuoApp reads from the project rather than a separate sheet, the number you agreed and the number you invoice are the same number. This removes the single biggest source of admin error in a contracting business — and most of the admin time with it.
Where the figures come from
An invoice or application is built from what's already on the project: the contract value, the works completed, the billing method you chose, and any retention or deductions that apply. You're not starting from a blank document — you're confirming what the project already knows.
Generating an application or invoice
From the project, open Invoicing and choose to raise an application or invoice for the period. DuoApp pulls the completed works through, applies the right calculations, and produces a document ready to review:
- Works completed — drawn from your priced schedule, specific works or sub works.
- CIS deductions — calculated against the labour element at the correct rate for the subcontractor's status.
- Retention — held automatically at the agreed percentage, and tracked for later release.
- VAT — applied correctly, including where the domestic reverse charge applies.
Review, approve, send
Nothing goes out until a person says so. Generated invoices can be routed through smart approvals for sign-off, then issued to the client with your branding. The approval and the issue are both recorded, so there's always a clear trail of who authorised what.
The re-keying that disappears
- Copying completed works from a tracker into an application
- Hand-calculating CIS on the labour split
- Working out and remembering retention each month
- Reformatting numbers to send to the client
Each figure is entered once, on the project, and every document downstream reads from it.
CIS done properly
UK construction billing lives and dies on getting CIS right. DuoApp applies deductions to the labour element at the correct rate based on the subcontractor's verified status — not a hardcoded cell that drifts out of date. The full detail is in CIS deductions and verification.
A clean trail for every figure
Every application and invoice keeps its history — what it contained, when it was issued, and who approved it. So when a client queries a valuation or HMRC asks you to substantiate a return, the answer is in the audit trail, not in someone's memory of an email.