Progress Invoices: Billing Big Projects in Stages

Big projects have a cash-flow problem: if you invoice everything at the end, you've financed months of work before seeing a cent. Progress (or milestone) invoicing splits the total into stages — 30% to start, 40% at a milestone, the rest on delivery — so each chunk of work is paid for as it happens. It's standard practice in design, development and construction for a reason: it keeps both sides honest about scope.

What each progress invoice should show

• The project — name it, so a client juggling several suppliers knows which project this stage belongs to.
• The stage — "Stage 2 of 3 – development (40%)". Numbering the stages kills the "is this the whole thing?" confusion.
• The stage amount — the money due for this milestone, not the full project total.
• The remaining balance — "remaining after this invoice: $4,000". Clients approve stage invoices more easily when they can see the whole picture.
• Reference to the agreed breakdown — a note pointing at the proposal ("per estimate #12") connects the invoice to the scope you both signed off.

Deposits and scope changes

A first-stage invoice often doubles as the deposit request — "50% to book the project". If scope grows mid-project, invoice the addition as its own line or its own stage instead of quietly padding a milestone; visible changes keep the relationship clean. And never send a stage invoice for work the client hasn't agreed is done — milestones are meant to be checkpoints, and invoices that arrive early teach clients to distrust the process.

How to create yours with SleekKitBox

1. Open the Progress Invoice template.
2. Fill in the project, the stage, the stage amount and the total project value.
3. Download and send it when the milestone is complete. Repeat for each stage with the same project reference.

If a client prefers a monthly availability fee instead of milestones, the retainer invoice fits better; subscription products are best billed with the recurring invoice.

Frequently asked questions

How many stages is normal? As few as you can get away with — two to four stages cover most projects. Every extra invoice is extra admin for you and extra friction for the client.

What percentage upfront? Enough to cover your early costs — a third to a half is common. Above that, clients start asking what happens if you disappear; be reasonable.

What if the client wants to pay the full amount at the end? Negotiable, but stage invoices protect you from financing the whole project — worth a conversation about why they matter to you.

👉 Create yours: free Progress Invoice template →