Billing a retainer correctly

What must a retainer contract state for correct billing?

• The monthly fee, net.
• Whether it is billed in advance or in arrears.
• The invoice day, or how long after the period it is billed.
• The start date and, for a fixed term, the end date and notice period.
• Any price increase: by how much, from when, and whether it repeats.
• The payment terms and any early-payment discount (Skonto).

If the contract is silent on one of these, Valtor takes the value from your billing policy, which you approve once for the workspace — or asks your reviewer. It never assumes the 1st of the month or 30 days to pay.

How is a part month calculated?

When a retainer starts or ends mid-month, the first or last invoice covers only part of the period. The contract or your billing policy sets the basis: calendar days, a 30-day month, or working days.

Example: a €12,500 retainer starts on 16 September and is prorated by calendar days. September has 30 days, 15 of them billable: €6,250 for September.

How is an agreed price increase applied?

An escalation clause raises the fee by an agreed percentage — once or repeatedly, from a fixed date or after a number of months, on the last increased amount or on the original one. Valtor applies it from the agreed date and shows the clause next to the increased amount.

Example: 3% after twelve months turns €12,500 into €12,875 from month 13.

What must a retainer invoice show in Germany?

Besides the mandatory details of § 14 (4) UStG, the invoice must state the service period (Leistungszeitraum) — for a retainer, the month it covers. From 2027, businesses with more than €800,000 turnover in the previous year must issue it as an e-invoice; Valtor issues XRechnung and ZUGFeRD.

What happens at the end of the term?

Valtor knows the notice period and opens a task 60 days before the notice deadline, so a renewal or termination is a decision, not an accident. An auto-renewing contract keeps billing; a fixed term ends on its end date.

Questions and answers