Late-payment interest calculator for Austria and Germany.

How do you calculate late payment interest in Austria?

You calculate late payment interest with a single formula: outstanding amount times interest rate divided by 365 times the number of days in default. On a claim of 10,000 euros, a rate of 10.73 percent and 60 days in default, that comes to 176.38 euros. The calculator on this page does exactly that arithmetic for you.

The calculation runs to the day. That means the actual calendar days between the due date of your invoice and the date you are calculating up to are counted, divided by a year of 365 days. This convention is the usual one in Austria for monetary claims. Compound interest does not arise: the calculation always runs on the outstanding principal claim, never on interest that has already accrued.

Late payment interest between companies and towards consumers

Austria works with two rates. Between companies a floating rate of 9.2 percentage points above the base rate applies, currently 10.73 percent per year. Towards consumers a fixed statutory rate of 4 percent per year applies. The higher business rate requires, among other things, attributable default; otherwise a business claim can also be subject to the 4 percent rate.

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As of 2026. Base rate 1.53 %, in force since 1 July 2025 and confirmed for 2026 (source: Oesterreichische Nationalbank). Once the reminders are done, the payment reminder generator writes the letter that puts the debtor in default.

When is a customer in default?

Default begins on the day after the due date. If your invoice states a payment term of 30 days, the interest clock starts on day 31. Between companies you do not need a prior reminder for this: default arises automatically once the agreed payment term expires. Where no payment term was agreed at all, the statutory period of 30 days from receipt and maturity of the invoice applies.

• Always put the payment term on the invoice in writing. Wording such as "promptly" leaves room for interpretation.
• Issue invoices immediately. The earlier the term starts, the earlier the interest runs.
• Document every reminder with a date. In a dispute the record counts, not the recollection. A clean reminder takes a few minutes with the payment reminder generator.

How much is late payment interest per day?

The daily interest follows from the outstanding amount times the interest rate divided by 365. On 10,000 euros at a rate of 10.73 percent that is 2.94 euros per day. Over 30 days it adds up to roughly 88 euros, over a full year to 1,073 euros. The calculator above shows that daily figure for your own amount as well.

A worked example from practice

Your company invoices a business customer for 15,000 euros with a payment term of 30 days. The customer pays only 60 days after the due date.

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Illustrative example, as of 2026. Calculated with 15,000 × 10.73 % ÷ 365 × 60 days. On top of the interest, between companies you are entitled to a flat 40 euros for the costs of collection, without having to prove each item.

How has the rate developed?

The rate between companies floats: it is tied to the base rate that the Oesterreichische Nationalbank sets on 1 January and on 1 July. What counts is the rate in force on the first day of the half-year in which the default begins. Since the peak in 2024 the rate has fallen noticeably.

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Source: Oesterreichische Nationalbank, base rate (Anknüpfungszinssätze), retrieved in July 2026. The rate between companies follows from the base rate plus 9.2 percentage points. The rate towards consumers remains unchanged at 4 percent per year.

What you can claim on top of the interest

Between companies you are entitled to a flat 40 euros per claim for the costs of collection, on top of the late payment interest. You can apply that amount without proving each item. If your actual costs are higher, for instance because you instruct a debt collection institute, you may claim the higher amount instead. What that means for you is set out on the page about debt collection costs: the default costs are borne by the debtor in arrears, your principal claim stays 100% yours.

If the invoice stays open despite interest and reminders, the overview unpaid invoice helps with the next steps, and when the customer stops responding to reminders altogether, customer not paying sorts through the options. Timing matters: business claims in Austria become time-barred three years after the due date, and the late payment interest is time-barred within the same period as the principal claim.