Interim and final invoices: separate billed work from payments

Keep three values separate

On a longer project, completed work, previously invoiced work and money received develop independently. Issuing an interim invoice does not record a payment. Keep project, customer, work period, invoice number and payment references clear from the quotation onwards.

In Germany, § 632a BGB sets conditions for interim payments based on the value of completed contractual work and a comprehensible statement. Prepare measurements, evidence and period. Distinguish planned materials from completed work and agree changes before billing. A document title alone does not settle tax treatment.

Choose the correct invoice workflow

In the web editor, Rechnungsart offers Standard, Abschlagsrechnung, Kumulierte Abschlagsrechnung and Schlussrechnung. Choose the appropriate type and project. Check customer, performance date or period, items, prices and tax details. Save and review the PDF.

For cumulative and final invoices, review Vorausgehende Rechnungen. Only use relevant earlier invoices for the same project, not an unrelated job merely sharing the customer.

Deduct previously invoiced work separately

The current cumulative invoice amount equals cumulative work minus work already invoiced. That deduction is independent of whether the previous invoice has been paid. It records no payment and does not change the previous invoice's outstanding balance.

Check each reference and its actual newly invoiced amount. Never add together the cumulative headline totals of several earlier invoices. Count each invoice once and reflect valid credits or cancellations in the billing state.

Allocate real payments to their invoices

An invoice's outstanding amount equals its invoice amount minus allocated payments. The project's outstanding receivable is the sum of invoice balances, accounting for valid corrections. Deductions, credits and discounts are not by themselves money received.

Check the actual bank receipt rather than inventing a payment to obtain a desired balance. Refunds and corrections also need clear references. Read invoice corrections.

Example: the invoice and project balance

These are comparable gross amounts; tax breakdown, special cases, discounts, retentions and refunds require separate review.

Value	Amount
Cumulative work	€20,712.84
Earlier invoice, unpaid	€15,186.50
Current interim invoice	€5,526.34
Payments on the current invoice	€0.00
Current invoice outstanding	€5,526.34
Earlier invoice outstanding	€15,186.50
Total project outstanding	€20,712.84

If €2,000.00 later arrives against the earlier invoice, its outstanding amount becomes €13,186.50. The current invoice remains €5,526.34 and the project balance becomes €18,712.84. The current invoice's payment request uses its own outstanding amount, not the whole project receivable.

For German VAT, § 14(5) UStG requires previously received partial consideration and associated VAT to be deducted in a final invoice where corresponding invoices were issued. Check the final breakdown, not just the last payable figure, with tax advice for special cases.

Review before issuing the final invoice

Check complete scope, relevant previous invoices, allocated payments and refunds, tax breakdown and balance, and necessary recipient references and appendices. Confirm format and delivery route using the e-invoice comparison and project completion checklist.

As of 16 October 2026. These workflow examples do not replace review of your project's contract and tax position.