Construction Invoice Generator
Generate a clean GST-compliant construction invoice with retention. No login — fill in, preview, then download.
This tool produces a draft invoice for your records. Confirm your ABN is current and that the “Tax invoice” label is shown to issue a valid Australian tax invoice.
Your details
Client
Invoice
Bank details
Line items
Description
Qty
Unit price
Amount
No line items yet. Add a labour, material, variation, or progress claim item to build your invoice.
Include GST (10%)
Apply retention (5%)
Withheld from the invoice subtotal.
Show 'Tax Invoice' label
Required wording for a valid AU tax invoice.
Live preview
Add your business details, client, invoice number and at least one line item to preview the invoice.
How it works
Behind the numbers
Each line item multiplies quantity by unit price. The subtotal sums every line, retention (if applied) is held against the subtotal, and GST (if applied) is calculated on the net after retention is held back. Total due equals subtotal − retention + GST.
Bank details and payment terms are written into the bottom of the preview — edit them on the form to keep the invoice up to date.
Formula
The maths, written out
Line = Qty × Unit Subtotal = Σ Lines Retention = Subtotal × Retention% GST = (Subtotal − Retention) × 10% Total due = Subtotal − Retention + GST
Worked example
A quick scenario
Frame & truss claim $18,500 + 15 windows × $240 ($3,600) + 22 hours × $95 ($2,090) = $24,190 subtotal. With 5% retention ($1,209.50) and 10% GST on the net ($2,298.05), the total due is $25,278.55.
Frequently asked
Is this a valid Australian tax invoice?
The generated invoice includes the fields a tax invoice typically needs: ABN, supplier details, recipient details, GST line, line items and total. To be a valid tax invoice you must include the words "Tax invoice" and confirm your ABN is current — this generator includes that label by default.
Do I need to charge GST?
Only if your business is registered for GST. Toggle GST off if you're not registered, and remove the GST line from the invoice.
Can I include retention on an invoice?
Yes — retention is held against the subtotal, then GST is calculated on the net (after retention). Toggle retention on and set the percentage.
Where does the data go?
Nowhere. The generator runs entirely in your browser. Nothing is sent to our servers.
Is this calculator free to use?
Yes. All calculators on Contractor Calc are free and do not require sign-up.
How accurate are the results?
The calculators use standard formulas. Results are estimates only and depend on the values you enter. Always check against your contract.
Can I export the results?
Most calculators include a download or copy-to-clipboard option for sharing with clients or storing in your records.