Late Payment Interest Calculator Switzerland (5%, Art. 104 CO)

Two questions matter: when does default begin, and how much interest can you charge? The rate is set by law (5% per year). With a fixed due date agreed, default begins when that date has passed; otherwise only with your reminder. This applies to money claims under Swiss law.

What the calculator does not cover · Jump to the result · Auf Deutsch: Verzugszins Rechner Schweiz

Your details

When does default begin? A fixed due date was agreed (for example «payable by 30.11.2026») No fixed due date: default begins with my reminder

Invoice amount in CHFOutstanding amount without interest. Example: 1250.50

Due date, or date the reminder reached the debtorInterest runs from the day after this date.

Or: invoice date (optional)Only if the due date above is empty and the term runs from the invoice date (fixed-due-date option).

Payment term in days (optional)For example 30. Due date = invoice date plus these days.

Calculate interest up toThe payment date, or today if not yet paid.

Day count The law prescribes no method. The difference is usually a few cents.

Interest rate in % (optional)Leave empty for the statutory 5%. A higher rate applies only if agreed.

Please enter the invoice amount, the date default starts and the payment date.

Late payment interest calculation (lezo.ch/late-payment-interest-calculator/)

Your result

–Default interest

–Interest days

–Total (amount + interest)

Workings

Easier to pay, fewer reminders. An invoice with a Swiss QR bill lets your client scan the code and pay in their banking app. There is a free QR-bill demo, and a pack of English invoice and reminder templates (CHF 19, one-off). You can look inside before buying.

How default interest is calculated

Establish default. If a fixed due date was agreed, the debtor is in default when that day has passed, without any reminder (Art. 102 para. 2 CO). Without such a date, the claim is due but default only begins with your reminder (Art. 102 para. 1 CO). Whether a payment deadline printed one-sidedly on an invoice counts as an agreed due date is disputed. If unsure, choose «default begins with my reminder».
Rate. The statutory default interest is 5% per year (Art. 104 para. 1 CO), even if the contract names a lower rate. A higher agreed rate stays valid (para. 2); between merchants a higher bank discount rate usual at the place of payment may apply (para. 3).
Count the days. The start date does not count, the payment day does. This is the usual, easy-to-follow count.
Calculate. Amount × rate × days / 365 (or 360).

Simple interest only, no compound interest: interest may not be charged on default interest (Art. 105 para. 3 CO).

What this calculator does not cover

Further damages beyond interest (Art. 106 CO) and collection costs.
Debt enforcement costs, court costs and legal fees.
Interest, annuities and gifts: special rules apply for the start of default (Art. 105 CO). Not calculated here.
Holidays and weekends. If the due date falls on a Sunday or public holiday, the next working day applies under Art. 78 CO. The calculator does not shift dates; it only points out weekends.
Special rules for consumer credit, rent, taxes and social insurance contributions, claims against public bodies and foreign currencies.
Part payments: calculate each part payment separately (the remainder anew from the payment date).
Agreements in your contract (other rates, consequences of default).

Guidance, not legal advice. The calculator applies Articles 102 and 104 CO (SR 220) in a simplified way. It does not know your contract and does not replace advice. Legal text: Code of Obligations on Fedlex (SR 220), English (translation without legal force) and German original. For large amounts or disputes, ask a legal adviser or your trade association.

Frequently asked questions

What is the default interest rate in Switzerland?

The statutory default interest is 5% per year (Art. 104 para. 1 CO). It applies when a debtor is late with a money payment. A higher rate is possible if agreed.

From when is default interest owed?

If a fixed due date was agreed, when that day has passed. Otherwise from the reminder that has reached the other side (Art. 102 CO). If unsure, send a reminder: then default is certain.

Must I send a reminder before charging interest?

Only if no due date was agreed. With an agreed due date, interest runs without a reminder. In practice most people remind anyway, so that amount, interest and deadline are documented in writing.

What happens to my entries?

The calculation runs in your browser. We receive no entries, store nothing and set no tracking cookies. After reloading, the form is empty. Details in the privacy policy.

Legal basis as checked on the German page (verzugszins-rechner), 06.11.2026. Please check the current version on Fedlex.