Payment Due Calculator

Payment terms sound trivial until an invoice goes unpaid. Suddenly every date matters: when is the customer in default? Which interest rate applies? How much can you demand without overreaching? The payment due calculator does the maths for you and lays out every step with the matching statute, so your dunning letter is not written into the blue.

It starts with the due date. You enter the invoice date and payment term - either as a number of days from the invoice date or as a fixed due date. Optionally you add when the customer received the invoice, because the 30-day rule under Section 286(3) BGB depends on receipt. If you agreed a cash discount, the tool also computes the discount window and the reduced amount payable.

The default start date is where most people slip. For B2B with an agreed term, default begins the day after the due date, calendar-determined under Section 286(2) BGB, without any reminder. For consumers (B2C) you need either a reminder or the 30-day automatic under Section 286(3) BGB, which only kicks in if the invoice carries the default notice. The calculator distinguishes these cases and shows you the right date.

Once the conditions are clear come the late-payment interest rates under Section 288 BGB. For consumer transactions it is five percentage points above the base rate, for transactions without consumer involvement nine points. The base rate changes every six months, and that is where it gets nasty: if your default period crosses a cutoff date, different rates apply to the sub-periods. The calculator uses the built-in Bundesbank base-rate series and computes segment-exact, day-exact per act/365. If you want to set your own base rate, you can.

Two things easily overlooked are built in. Section 271a BGB caps long payment terms: over 60 days in B2B (over 30 days for public-sector clients) is only valid if expressly agreed and not grossly unfair. And the limitation period under Sections 195, 199 BGB runs three years from the end of the year the claim arose. The calculator flags both so no claim quietly slips away.

Finally you can export the due date as an ICS file for your calendar, or hand it to the deadline guardian so a reminder nudges you in time. Everything runs in your browser, no amounts and no customer data leave your device. This is not legal advice, it is a calculating servant - but one that knows the statutes.