What is a dunning run?
The term dunning run comes from accounting: instead of chasing every overdue invoice individually, you check all open items at regular intervals in one go. For each invoice past its payment term, the dunning run decides whether a reminder is due and which one. The result is a list of dunning candidates – customers who should receive a payment reminder, a dunning letter or a final notice.
Dunning runs exist at every scale. Small businesses often use a spreadsheet and a fixed date at the end of the month, larger ones a module of their accounting software or a dedicated receivables management solution. The principle stays the same: a dunning run turns many individual decisions into a repeatable dunning procedure.
How a dunning run works, step by step
1. Update open items
A dunning run is only as good as its data. Before any reminder goes out, all incoming payments must be recorded and assigned to the right invoices. Skip this step and you will chase customers who have already paid – the most common and most irritating mistake in dunning. The guide automatic payment matching for incoming payments explains how to solve this reliably.
2. Determine dunning candidates
Next, the run calculates for each overdue invoice how many days it is late and which level was sent last. This defines the next action. A grace period after the due date and fixed intervals between levels, such as seven or fourteen days, are common. Which levels make sense is covered in dunning levels: stages, deadlines and fees.
3. Check exceptions
Not every candidate should be chased automatically. Before sending, remove customers with an open complaint, an agreed instalment plan or a missing contact address. A good dunning run flags these cases clearly instead of skipping them silently.
4. Create and send reminders
For the remaining candidates the letters are generated – with invoice number, open amount, due date and, where applicable, a dunning fee. Attaching the original invoice saves follow-up questions. Delivery is by email, by post or both.
5. Document the result
Every reminder sent is recorded with its date and level. You need this record if a customer denies receipt, when you hand a case to a collection agency or when you apply for a court payment order.
How often should a dunning run take place?
There is no legal requirement. In practice, three rhythms work well:
- Daily: every invoice is chased on exactly the day its deadline expires. This is the most consistent approach and costs no extra effort with software.
- Weekly: a fixed weekday suits teams that still review reminders manually. Invoices then stay open up to six days longer than necessary.
- Monthly: acceptable with only a few invoices per month; with regular invoicing it gives away liquidity.
Reliability matters more than the rhythm itself. A dunning run that is skipped in busy weeks tells customers that payment terms are negotiable.
Legal framework in Germany
There are no formal requirements for the dunning run itself. A few rules of the German Civil Code (BGB) are still worth knowing:
- Default: under Section 286 BGB, a debtor usually falls into default through a reminder after the due date. If the payment date is fixed by the calendar, no reminder is needed. At the latest 30 days after the due date and receipt of the invoice, default occurs even without a reminder – for consumers only if the invoice expressly points out this consequence.
- Default interest: under Section 288 BGB it amounts to 5 percentage points above the base rate, and 9 percentage points for transactions not involving a consumer.
- Lump sum: towards businesses in default you can additionally claim a flat fee of EUR 40 (Section 288 (5) BGB).
- No duty to send three reminders: the widespread belief that three reminders are required before legal action is wrong. Several levels still make sense because most overdue invoices were simply forgotten.
- Limitation: an out-of-court reminder does not suspend the limitation period. To secure a claim you need, for example, a payment order in the court dunning procedure (gerichtliches Mahnverfahren).
When should you pause a dunning sequence?
An automated dunning run only pays off if it stops in the right places. Take a customer or a single receivable out of the dunning sequence in these situations:
- Complaint or query: if a customer disputes the invoice or a delivery is missing, resolve the issue first. Another reminder escalates the conflict.
- Agreed instalments or deferral: as long as the customer keeps to the agreement, the receivable does not belong in the regular dunning run.
- Payment announced or on its way: if the customer has confirmed the transfer, wait for the payment instead of sending another reminder.
- Undeliverable messages: if a dunning email bounces, check the address or switch to postal delivery first.
- Insolvency or litigation: different rules apply here; an automated dunning run is the wrong tool.
- Key account in a sensitive phase: during contract negotiations, a personal message can be wiser than a standard letter.
Every pause needs a reason and ideally an end date. Open-ended exceptions without a note are why receivables go unnoticed for months.
Common mistakes in dunning runs
- Dunning without current payment data: a reminder for a paid invoice costs trust.
- Unclear texts: without invoice number, amount or bank details, payment is delayed even further.
- Intervals that are too long: sending the first reminder only after 60 days effectively grants a longer payment term.
- No escalation: a dunning run without a final level ends in a loop of reminders without consequences.
- No evaluation: without key figures you cannot tell whether the dunning run works. Useful measures are covered in accounts receivable KPIs: calculating and reducing DSO.
How acucollect automates your dunning runs
acucollect, the receivables management software by RLOX (product page in German), runs dunning automatically based on the invoices in Lexware Office, sevDesk or Odoo 19:
- A schedule instead of a calendar entry: you decide whether the dunning run starts daily, weekly or monthly at a set time. Invoices marked as paid in your accounting system are automatically excluded at the next sync.
- Dunning candidates with context: the list shows invoice number, days overdue, open amount and the next level for each customer. A missing email address is flagged immediately.
- Pause precisely: you can skip individual candidates in the current run. A dunning block takes a debtor out with a mandatory reason and an optional end date; afterwards the procedure continues where it stopped. Receivables in a payment plan are excluded automatically.
- Control before the first send: reminders from the first automatic run are held back for your approval. A preview shows, with real invoices, what your customers would receive.
- Complete reminders: the original invoice is attached to every dunning email; for each level you choose email, letter or both.
How the individual levels, deadlines and fees are set up is described in dunning levels. All topics at a glance are collected in our guides to dunning and accounts receivable management.
