Every self-employed person knows the phone call: "I'm afraid I can't pay the invoice all at once. Can we work something out?" Now you have two options. Option one: you refuse, send reminders and possibly initiate debt enforcement. Option two: you offer an instalment plan. But if you want to agree on an instalment plan, don't do it casually on the phone – do it in writing, properly and confidently. Then an instalment plan isn't generosity, it's strategy: you get your money in smaller steps, the client keeps their dignity, and you lose none of your legal protection compared with the "all at once" scenario.

Without a written agreement, an instalment plan is a paper tiger without teeth. You lose time, the limitation period keeps running, and in the worst case you end up worse off than before. With an acceleration clause, clear dates and a documented dunning process, an instalment plan is one of the most effective tools in receivables management – and for amounts where debt enforcement is only marginally worthwhile, often the only realistic solution.

In this guide, I'll show you when an instalment plan makes sense, what the agreement has to contain (including a copy-paste template), what you need to know about the acceleration clause, default interest and MWST (Swiss VAT at 8.1%) – and what to do if the client defaults anyway. With concrete CHF amounts and three stories from practice.

Key Takeaways

• Always in writing – a verbal agreement is almost worthless in a dispute. Use the template below, fill it in and have it signed.
• Include an acceleration clause – if one instalment is late, the entire remaining amount becomes due immediately. Otherwise you'll be chasing CHF 900.00 instalments instead of demanding CHF 5,340.00 at once.
• 5% default interest from the reminder – applies automatically under OR Art. 104 (Swiss Code of Obligations), even without an agreement. But you can also agree on your own rate in the contract.
• Declare Swiss VAT per instalment – each incoming instalment contains its MWST (Swiss VAT) share of 8.1%; you declare it on receipt, not on the invoice date.
• Prepare the escalation – if an instalment is missed: brief reminder, trigger the acceleration clause, then a final notice with a deadline and, if necessary, debt enforcement (advance approx. CHF 20.00–40.00).

Agreeing payment plans: when it makes sense – and when it doesn't

First, the most important distinction: a client who calls you of their own accord and asks for instalments is a completely different category from one who stays silent. In the first case, you have someone who wants to pay and just can't right now. In the second case, you have a communication problem – and a payment plan doesn't solve a communication problem.

An instalment plan is worthwhile when:

• The client reaches out early and on their own initiative – not only after the third collection notice.
• The crisis seems plausible and temporary: a divorce, a renovation, a short-term loss of orders on the client's side.
• The business relationship is valuable and you want to keep it.
• The amount is too large for the client but too small for a long legal battle – for most self-employed people, that's between a few hundred and a few tens of thousands of francs.
• The client has experienced you as professional: anyone who negotiates in a structured, written way doesn't come across as a pushover, but as someone who takes their money seriously.

Keep your hands off it when:

• The client no longer responds at all. Then continue with the normal dunning process and, if necessary, debt enforcement.
• The ability to pay is permanently gone. A payment plan then just prolongs the death of the claim.
• It's a pattern. For business clients, a look at the Zefix commercial register beforehand is worthwhile: if you spot bankruptcy entries or anything resembling a silent liquidation, demand payment in advance instead of offering instalments.
• The total amount is small. For CHF 150.00 in three instalments of CHF 50.00, the administrative effort isn't worth it – a clear collection notice is faster.

As a rough rule of thumb: an instalment plan is worthwhile from a total amount of around CHF 500.00 and with a client whose story you believe. Anything below that, or with doubtful communication: standardized dunning process.

Mini-story: Miriam, physiotherapist from Bern

Miriam, a physiotherapist from Bern, had an open invoice of CHF 2,400.00 after a completed course of treatment. The patient got in touch of his own accord – financially, things had suddenly fallen apart. Miriam offered six monthly instalments of CHF 400.00, the first due immediately. She had it confirmed in writing with a short agreement including an acceleration clause. All six instalments arrived on time, and the patient remained loyal to her practice. Her takeaway: "I didn't give anything up – I just collected in smaller steps."

The instalment payment agreement: what belongs in it

Why in writing at all? Three reasons. First: evidentiary value. A signed instalment payment agreement is at the same time a written acknowledgement of debt – that's worth its weight in gold if things do end up in debt enforcement, because with an acknowledged claim, the removal of the legal objection is much easier. Second: it forces both sides to talk precisely about dates and amounts instead of vague assurances ("Just send something whenever it suits you"). Third: it disciplines the client – a signed payment plan is taken more seriously than a phone call.

These points belong in every instalment payment agreement:

• Parties: full names and addresses; for companies, the name as registered in the commercial register.
• Reference invoice: invoice number, invoice date and total amount incl. MWST (Swiss VAT).
• Instalment plan: number of instalments, amount per instalment and concrete due dates – not "monthly", but "30 November 2026".
• First instalment immediately or very soon: someone who doesn't pay the first instalment right away often never pays at all.
• Payment method: QR-bill (Swiss QR invoice) by post, Twint or bank transfer – the simpler, the better.
• Acceleration clause: the most important point, see next section.
• Default interest: from the reminder, standard 5% (OR Art. 104).
• Reminder and collection costs: borne by the debtor, insofar as legally permissible.
• Signatures of both parties – or at least an explicit email confirmation ("I agree to this instalment plan"). The signature is better.

Copy-paste template:

Instalment Payment Agreement

between
[Your name / your company, address, UID no. if applicable] ("Creditor")
and
[Name, address of the client] ("Debtor")

Re: Invoice No. [2026-0142] of [01.09.2026]
for CHF [4,800.00] incl. MWST (Swiss VAT)

1. The debtor confirms receipt of the invoice and
   acknowledges the open amount of CHF [4,800.00].

2. The amount will be paid in the following instalments:
   – CHF [1,200.00] payable by [31.10.2026]
   – CHF [900.00]  payable by [30.11.2026]
   – CHF [900.00]  payable by [31.12.2026]
   – CHF [900.00]  payable by [31.01.2027]
   – CHF [900.00]  payable by [28.02.2027]

3. Payment is made by QR-bill (Swiss QR invoice; note
   the reference number) or Twint.

4. Acceleration clause (Verfallklausel): If the debtor
   falls more than [10] days behind on an instalment,
   the entire remaining open amount becomes due
   immediately.

5. On the open amount, the debtor owes default interest
   of [5]% per year from the date of the reminder.

6. Reminder and collection costs are borne by the debtor,
   insofar as legally permissible.

Place, date: _________________
Signature creditor: _________________
Signature debtor: _________________

Set the instalments realistically. Four instalments the client can manage are worth more than twelve that defeat them. And: the original invoice must comply with Swiss VAT requirements – all mandatory information, correct MWST rate, UID number. If you're unsure what belongs on a Swiss invoice: our invoice template shows you the complete structure including all mandatory fields.

How to word the acceleration clause correctly

The acceleration clause (Verfallklausel) is the centrepiece of every instalment payment agreement. Without it, the following applies: each individual instalment is its own small claim. If one fails, you have to send reminders, set deadlines, initiate debt enforcement – while the next instalments keep running and you'll soon be doing the same thing all over again. With an acceleration clause, the logic flips: a single default makes the entire remaining amount due immediately. That's the decisive difference between "chasing CHF 900.00" and "demanding CHF 5,340.00".

Here's what a clean acceleration clause sounds like:

"If the debtor falls more than 10 days behind on an instalment, the total of all remaining open instalments becomes due immediately without further reminder."

Three practical tips:

• Write it, don't say it. The clause has to be in the agreement, clearly worded and not hidden in the small print. Surprising clauses tend to get struck down in court.
• Build in a short grace period. The 10 days in the clause aren't an end in themselves: they come across as fair and avoid the impression that you've set a trap for the client. At the same time, you keep your leverage.
• Be careful with consumers. Instalment payments to private individuals can fall under the Swiss Consumer Credit Act (KVKG). In that case, the law requires you to send a written reminder after the first late instalment and, as a rule, to allow at least 14 days before escalating further. Whether the KVKG applies to your specific case depends, among other things, on the amount and the form of the contract – you can find the current version on fedlex.admin.ch; if in doubt, a brief legal consultation helps.

Mini-story: Rafael, painter from Basel

Rafael, a painter from Basel, had an open invoice of CHF 8,900.00 after repainting an apartment. The client asked for an instalment plan. Rafael agreed: five instalments of CHF 1,780.00, the first due immediately – with an acceleration clause and 5% default interest. The first two instalments arrived on time, the third didn't. On the phone: "Definitely next week." Rafael waited out the 10 days of the clause, then triggered it and wrote a single collection notice with a 10-day deadline for the entire open remainder of CHF 5,340.00. It was paid within eight days, in full. His comment: "Without the clause, I'd have spent months chasing mini-instalments by phone."

Interest and costs: what you're allowed to charge

Many self-employed people believe they have to give everything up when agreeing on an instalment plan. The opposite is true: you're allowed to charge interest and costs with a payment plan too – the only standard is that it stays fair.

Default interest. From the moment the client is in default – with instalment payment agreements, usually with the reminder after an instalment falls due –, they owe default interest. Without a specific agreement, that's 5% per year under OR Art. 104. But you can also set a different rate in the agreement, higher or lower. Important: the interest only runs from default, not from the day of signing. Anyone demanding interest on all instalments from day one comes across as greedy and risks the client never entering the plan at all. Keep it moderate: a rate far above 5% can be deemed inadmissible. Stay close to the statutory standard.

What does 5% mean concretely? On an open remaining amount of CHF 5,340.00, that's CHF 267.00 per year – roughly CHF 22.25 per month. On small remaining amounts, the interest isn't a business model, but it shows the client that not paying has a price.

Reminder fees. Customary and usually unchallenged by courts are CHF 10.00 to CHF 20.00 per collection notice – provided you only send reminders after the due date and document the effort. What isn't allowed is turning reminder fees into a profit centre.

Keep it lean. Every fee you add increases the risk that the client abandons the plan. A good compromise from practice: write costs and interest into the agreement (they work even without being enforced), but don't actually claim them if the plan succeeds. The client feels it: paying on time pays off.

Swiss VAT on instalment payments: how to declare it correctly

The most common question in the context of instalment plans: do I have to issue a separate VAT invoice per instalment? The short answer: no. The original invoice remains the only invoice – for the full amount including MWST (Swiss VAT). The instalments are payments against that invoice.

The timing. Declaring follows the receipt principle: every incoming instalment is a partial payment, and the MWST share it contains is declared in the accounting period in which the instalment actually reached you – not already when the invoice was issued. This is regulated by the Swiss VAT Act (MWSTG); you can find the current wording and the details on the tax period on fedlex.admin.ch or in the guidelines of the FTA (ESTV).

An example with 8.1% Swiss VAT: if an instalment of CHF 1,000.00 comes in, it contains CHF 74.93 MWST (CHF 925.07 net + CHF 74.93 MWST). Exactly this share is declared in the period of receipt. Calculated this way, all instalments together add up precisely to the VAT of the total invoice.

The invoice itself. The original invoice must meet the mandatory information requirements – your UID number, the MWST rate and the MWST amount, the invoice date and so on. What information belongs on it is regulated in Art. 26 MWSTG. It is also permissible and advisable to mention the instalment plan directly on the invoice ("payable in 5 monthly instalments per agreement of 22.09.2026"). That creates clarity for both sides and for the tax office.

Instalments and payments on account are not the same thing. A payment on account is a payment before or during the delivery of the service – an advance that you offset against a service still in progress. An instalment payment in the sense of this article is the subsequent payment of an already delivered, fully invoiced service. For payments on account covering genuine partial services, partial invoices can make sense; for a payment plan for a completed invoice, they don't.

And one practical tip in the other direction: if you yourself ever fall behind on your MWST, the FTA (ESTV) accepts payment plans – you can submit a payment plan proposal online.

A QR-bill per instalment: how everything stays allocatable

The biggest practical annoyance with instalment payments is partial receipts you can't allocate to a claim. The solution is simple: send a separate QR-bill (Swiss QR invoice) with its own reference number for each instalment. Your bookkeeping then matches the payment automatically to the correct instalment, and you never have to puzzle over what the client meant by "transferred 500 once".

Here's how to implement it:

1. One QR-bill per instalment, each with its own payment part and its own reference number.
2. Don't send them all at once. Send each instalment invoice five to seven days before its due date – not the whole package up front. Otherwise the client pays out of order.
3. Build in a reminder. Three days after an overdue instalment, a short, friendly payment reminder – as with any other invoice. When exactly default begins and how reminders, collection notices and interest interact is covered in our guide on payment terms and default in Switzerland.
4. Offer Twint. Private clients in particular pay instalments more reliably when the payment method is easy.

Sounds like work? It doesn't have to be. If you create your invoices with Magic Heidi, you can set up the instalments once as recurring invoices: QR-bill per instalment with the correct reference number, automatic reminder, clean posting on receipt of payment. How such a QR-bill is structured and which fields are mandatory is shown in our guide on creating a QR-bill.

You agreed on an instalment plan, but the client still doesn't pay

Even the nicest payment plan can fail. The difference from a verbal arrangement: now you have a plan for this case. The escalation runs in four stages:

Stage 1: The conversation (day 3–5 after the due date). The first missed instalment is usually an oversight – a forgotten transfer day, a missed e-banking appointment. A short email or call: "We haven't received the instalment of 31.10 – please pay by date." Stay friendly, but be concrete.

Stage 2: Trigger the acceleration clause (day 10–14). If the instalment still hasn't arrived and keeps slipping even after the conversation, pull the trigger: you invoke the acceleration clause and make the entire open remaining amount due. With consumers, observe the KVKG grace period (written reminder, as a rule at least 14 days). From now on, in writing, with a date.

Stage 3: The final collection notice with a deadline and threat of enforcement. Concretely: full remaining amount including default interest (5% from the reminder) plus a reminder fee of CHF 10.00 to CHF 20.00, 10-day deadline, with the explicit sentence "otherwise we will initiate debt enforcement". The sentence only works if you follow through.

Stage 4: Debt enforcement. Now there's no point in discussing. How to initiate debt enforcement step by step – from the request to the debt enforcement office to the payment order, with an advance on costs from around CHF 20.00 – is covered in our guide on initiating debt enforcement in Switzerland. Your advantage over a creditor without an agreement: the signed instalment payment agreement is a written acknowledgement of debt. If the debtor files a legal objection, removing it becomes much easier.

One thought on patience: debt enforcement is only worthwhile once it's clear the payment plan has failed – not at the first broken date. The flip side: anyone who grants "one last chance" at the third default will reap the fourth. And if there really is nothing to collect in the end, the limitation period keeps running – how and when you can push back is covered in our article on when invoices become time-barred in Switzerland.

Mini-story: Stefan, photographer from St. Gallen

Stefan, a wedding photographer from St. Gallen, had an open invoice of CHF 3,600.00 and agreed on four instalments of CHF 900.00 with the bridal couple. The first instalment didn't come. Stefan sent a friendly reminder, got a "sorry, next week" – and nothing. After 10 days he triggered the acceleration clause, made the full CHF 3,600.00 due and set a 10-day deadline with the threat of enforcement. Nothing again. So he initiated debt enforcement, advance CHF 30.00. Eight days after the payment order was served, the transfer arrived: CHF 3,600.00 plus default interest. Stefan's comment: "The payment plan wasn't a weakness. It was proof that the couple never disputed the debt – that made the enforcement massively easier."

Conclusion: Agreeing on an instalment plan isn't giving something up, it's a receivables management tool with a safety net. The formula for success is short: written agreement, realistic instalments, acceleration clause, 5% default interest from the reminder, one QR-bill per instalment – and a clear escalation ladder in case the client defaults after all. If you don't want to manage instalments, reminders and collection notices by hand, Magic Heidi does it for you: recurring QR-bills, automatic reminders, seamless documentation. Prices start at CHF 25.00 per month – well below what comparable tools cost.