For larger projects, it is common not to invoice everything at once. Advance payments, partial invoices and final invoices are part of daily business for many self-employed professionals. But how do you book them correctly?
01Clarifying the Terms
| Term | Definition | Typical Use |
|---|---|---|
| Advance payment (deposit) | Payment before the service begins | Pre-financing materials, securing the contract |
| Progress payment | Payment during an ongoing project | Large projects, construction, IT projects |
| Partial invoice | Invoice for services already rendered | Completed project phases |
| Final invoice | Closing invoice for the entire contract | Project completion, remaining balance |
02How to Book in Simple Bookkeeping
In cash-basis accounting, the cash flow principle applies: you book each payment when the money actually flows. How to create partial invoices and deposits in practice is covered in a separate article. The basic principle is simple:
- Advance payment: Book as income as soon as the money arrives in your account
- Partial invoice: Book as income as soon as it is paid
- Final invoice: Book the remaining amount as income as soon as it is paid
03Practical Example: Web Design Project
You are building a website for CHF 10,000 (excl. VAT). Three payments are agreed: 30% advance payment, 40% after design approval, 30% upon project completion.
| Phase | Amount | Booked as Income |
|---|---|---|
| Advance payment (contract awarded) | CHF 3,000 | Upon receipt in January |
| Partial invoice (design approval) | CHF 4,000 | Upon receipt in March |
| Final invoice (go-live) | CHF 3,000 | Upon receipt in May |
| Total | CHF 10,000 |
04VAT on Partial Invoices
If you are subject to VAT, you must show VAT separately on each partial invoice. Also make sure to include all mandatory invoice details. VAT is calculated on the partial amount -- not on the total contract value.
On the final invoice, only the VAT on the remaining amount is shown. Important: The sum of all partial VAT amounts must equal the VAT on the total amount.
| Invoice | Net | VAT 8.1% | Gross |
|---|---|---|---|
| Advance payment | CHF 3,000.00 | CHF 243.00 | CHF 3,243.00 |
| Partial invoice | CHF 4,000.00 | CHF 324.00 | CHF 4,324.00 |
| Final invoice | CHF 3,000.00 | CHF 243.00 | CHF 3,243.00 |
| Total | CHF 10,000.00 | CHF 810.00 | CHF 10,810.00 |
05Practical Tips
- Define the payment schedule in the contract -- this avoids disputes
- Number each partial invoice separately (e.g. INV-2026-042a, INV-2026-042b)
- List all previous payments on the final invoice and deduct them
- Don't wait too long -- issue the final invoice immediately after project completion