What Is Dunning? The Modern Dunning Process, Explained (2026)

Dunning is the systematic process of communicating with customers to collect on overdue invoices and unpaid balances. Instead of a single awkward "did you get my invoice?" email, dunning is a planned sequence of reminders and follow-ups that starts before an invoice is even due and escalates politely over time until the bill is paid. Done well, it is one of the highest-leverage things a finance team can run, because every day an invoice sits unpaid is cash you have earned but cannot use. This guide explains what dunning is, where the word comes from, why it matters, and what a modern dunning process looks like in 2026.

What is dunning, exactly?

In plain terms, dunning is how you ask to get paid, on a schedule, consistently, across every open invoice. It covers the friendly nudge a few days before the due date, the reminder on the day payment is due, and the steadily firmer follow-ups that go out as an invoice ages past 30, 60, and 90 days. The communications themselves are often called dunning notices or dunning emails, and the whole orchestrated effort is your dunning process.

The word has an old and slightly unflattering history. "To dun" meant to demand payment of a debt, and one popular story traces it to a 17th-century English bailiff named Joe Dun who was famously effective at collecting on debts. The modern practice has moved a long way from a bailiff at the door. Today, good dunning is less about pressure and more about being organized, timely, and easy to pay, while keeping the relationship intact.

Why dunning matters: DSO and cash flow

Most B2B businesses do not have a sales problem. They have a collection problem. The invoices go out, the work is delivered, and then the money trickles in weeks late. The metric that captures this is days sales outstanding, or DSO, which measures the average number of days it takes to collect after a sale. A high or climbing DSO means cash is trapped in your accounts receivable instead of funding payroll, inventory, and growth.

A disciplined dunning process is the single most direct lever on DSO. When customers are reminded before the due date, contacted promptly the moment a bill goes overdue, and followed up with on a predictable cadence, they pay sooner. Companies that run consistent dunning routinely get paid 15 to 25 percent faster and pull their DSO down meaningfully, for example from the low 50s into the mid 30s. That is real money that shows up in your bank account weeks earlier, with no change to your prices or your sales volume.

The modern dunning process, stage by stage

A modern dunning sequence is a timeline of touches that begins before the invoice is overdue and escalates as it ages. The exact timing should match your terms and your customers, but the shape below is a reliable starting point.

• Pre-due reminder (about 5 to 7 days before the due date): a short, friendly heads-up that the invoice is coming up, with the amount, the due date, and a payment link. This alone prevents a surprising number of "I forgot" late payments.
• Due-date notice (on the day): a neutral reminder that payment is due today, restating the invoice details and how to pay.
• 1 to 30 days overdue (gentle nudges): one or two polite follow-ups assuming good faith. The tone is "just a friendly reminder that invoice 2047 is now past due." Most invoices clear here.
• 31 to 60 days overdue (firm but friendly): the message gets more direct and the cadence tightens. You confirm the amount, reference any prior reminders, and ask for a specific payment date.
• 61 to 90 days overdue (escalation): follow-ups move beyond email to other channels, and you reference late fees if your terms allow them. You want a commitment, not another open loop.
• 90+ days overdue (final notice and last resort): a clear final-notice communication, a request for a promise-to-pay, and only then, if all else fails, escalation to a collections agency or a payment plan.

The other half of escalation is the channel. Early in the sequence, email does most of the work. As an invoice ages, a single channel stops being enough, so a strong process layers in additional touchpoints: email first, then SMS, then a phone call or an AI voice call, and finally a structured promise-to-pay before any talk of collections. Multi-channel automated payment reminders get more eyes on the message and dramatically improve response rates compared to email alone.

Dunning emails that actually get paid

Dunning emails are the backbone of the sequence, so they deserve care. The best ones are short, specific, and make paying the obvious next step. A good dunning email includes the invoice number, the amount due, the original and current due date, a clear payment link or instructions, and a single direct ask. Avoid burying the request under apologies or long explanations. You are not asking for a favor. You are reminding someone of a commitment they already made.

A simple, effective body reads something like: "Hi Sam, invoice 2047 for $4,820 was due on June 15 and is now 12 days past due. You can pay securely here. If it is already on its way, please ignore this note, and if anything is holding it up, just reply and let me know." It is human, it is specific, and it makes the path forward effortless.

Soft vs hard dunning: staying on-brand

Dunning communications fall on a spectrum from soft to hard. Soft dunning is the relationship-preserving end: friendly reminders, the benefit of the doubt, and helpful tone. It assumes the customer simply forgot or got busy, which is true the vast majority of the time. Hard dunning is the firm end: final notices, references to late fees, service holds, and escalation. Most invoices should never reach it.

The art is matching the firmness to the situation while never sounding like a debt collector chasing a stranger. These are your customers, and you want them to keep buying from you. That means keeping every message on-brand: your company name, your voice, your colors, and a tone that is calm and respectful even when it is firm. A good dunning sequence starts soft and only hardens gradually, and only for the small minority of invoices that genuinely need it.

The goal of dunning is not to win an argument. It is to get paid this week and still have a happy customer next quarter.

Dunning best practices

Across thousands of finance teams, the same handful of practices separate a dunning process that works from one that quietly leaks cash:

• Be consistent. A predictable cadence that goes out every time beats sporadic, heroic chasing. Customers learn that your invoices get followed up on, so they prioritize them.
• Get the timing right. Start before the due date, contact promptly when an invoice goes overdue, and keep a steady rhythm rather than long silences punctuated by panic.
• Personalize. Use the contact's name, the specific invoice, and the real amount. Generic blasts feel like spam and get ignored.
• Make payment effortless. Every message should include a one-click payment link and clear instructions. Friction in paying is friction in getting paid.
• Match tone to age. Stay soft early, firm up gradually, and reserve hard dunning for the genuine stragglers.
• Track and follow up. Log promises-to-pay and circle back the moment one is missed. An unkept promise is the most important signal in your aging report.

For a deeper toolkit, see our guide on how to get customers to pay invoices faster, which expands these tactics into a full playbook.

Manual dunning vs automated dunning

Manual dunning is what most small finance teams do at first: someone opens the aging report, sorts by oldest, and works down the list sending emails and making calls. It works, but it is slow, easy to drop when month-end gets busy, and it eats 20 or more hours a week of skilled time. Worse, consistency is the first thing to suffer, and inconsistent dunning is the main reason DSO creeps up.

Automated dunning fixes the consistency problem. With dunning management software, the sequence runs itself: reminders fire on schedule, follow-ups escalate automatically, and nothing falls through the cracks because someone was on vacation. Good collections automation software personalizes each message, respects your terms, and keeps a clean record of every touch, so your team spends its time on the handful of accounts that need a human, not on copy-pasting the same three emails all day.

Dunning on autopilot with an AI AR agent

The newest step beyond automated reminders is a true AI accounts-receivable agent that does not just schedule the messages but runs the entire dunning sequence end to end. Connect QuickBooks, Xero, or NetSuite, and the agent reads your live aging report and chases every open invoice across channels: it sends the pre-due reminder, the due-date notice, and the escalating follow-ups by email, then layers in SMS and, when an invoice ages far enough, a live AI phone call. It captures promises-to-pay, follows up when they slip, and only flags the rare account that truly needs you.

Because it works on top of your existing books, it also applies incoming payments to the right invoices, keeps the ledger reconciled, and predicts when each customer will actually pay, so your dunning becomes proactive instead of reactive. It is the work of a full AR desk, running 24 hours a day, for a flat monthly fee, and we never take a percentage of what we collect. You can compare the approaches across our AR use cases or see the flat-fee plans on our pricing page.

Dunning will never be anyone's favorite task, but it does not have to be yours. Connect your accounting system and let your AI AR agent run the full dunning sequence on autopilot, so the reminders go out on time, every time, the cash lands sooner, and your DSO finally starts moving in the right direction.