E-Rechnung für Kleinunternehmer: half exempt, half obliged

The Kleinunternehmer regime of § 19 UStG covers businesses whose total turnover did not exceed €25,000 in the previous calendar year and does not exceed €100,000 in the current one; within it, sales are tax-exempt and invoices carry no VAT. The thresholds are the ones to watch: staying under both keeps you in the regime, and the special e-invoicing treatment hangs on that status.

The status is about your size, not your counterparties. A Kleinunternehmer invoicing businesses is still doing domestic B2B, which is exactly the territory the e-invoicing mandate regulates, and that is why the reform had to say something about small entrepreneurs at all.

Kleinunternehmer never have to issue e-invoices. The rule sits in § 34a UStDV, added by the Jahressteuergesetz 2024, and it is written generously: an invoice for the tax-exempt Kleinunternehmer turnover can always be transmitted as a sonstige Rechnung, in the law’s word, "immer". This is not a transition rule with an expiry date; while the Kleinunternehmer status holds, paper and PDF remain permanently sufficient.

Two footnotes keep the picture honest. Sending a sonstige Rechnung electronically, a PDF by email, still requires the recipient’s consent under the general rules, though consent can be informal and is routinely implied by paying without objection. And nothing forbids a Kleinunternehmer from issuing real e-invoices voluntarily: since every business must be able to receive them, no consent is needed, and larger customers may quietly appreciate it.

The BMF FAQ says it in one sentence: Kleinunternehmer are exempt from issuing e-invoices, but must nevertheless be able to receive them. The receiving duty of January 1, 2025 knows no size threshold, and the BMF explicitly foresees no exceptions. Your landlord’s property company, your phone provider, your wholesaler, any of them may switch to structured invoices at will, and some already have.

What receiving means in practice is modest but real: an email inbox suffices as the channel, the arriving file is XML or a hybrid whose decisive content is XML, and it must be retained for eight years with the structured part unaltered. A Kleinunternehmer who prints incoming XRechnungen for the Steuerberater folder is archiving the wrong thing.

Nobody expects an AP department from a one-person business. This covers the duties:

• A dedicated invoice email address. One inbox for incoming invoices, checked regularly, so structured files do not drown between newsletters.
• A way to read e-invoices. A free viewer, or the free Peppol e-Invoice Extractor linked below, turns XRechnung XML and ZUGFeRD data into readable fields when you need to check an amount.
• Archiving that keeps the original file. Store the received file itself, unaltered, for eight years; folders with a backup or your accounting tool’s document store both work if nothing rewrites the file.
• An eye on the thresholds. Track turnover against the €25,000 and €100,000 lines of § 19 UStG, because leaving the regime ends the § 34a issuing exemption too.
• Optional: voluntary e-invoicing. If your customers are businesses, issuing XRechnung or ZUGFeRD voluntarily makes you the easiest supplier in their pipeline, and your invoicing software very likely already exports it.

Exceeding the § 19 thresholds ends the Kleinunternehmer treatment, and with it the § 34a exemption; from then on the general rules apply. For issuing, that means the standard timeline: businesses whose prior-year turnover stays at or under €800,000 must issue e-invoices for in-scope domestic B2B sales from January 1, 2028, larger ones from January 1, 2027. Growth is the point at which the deadlines guide becomes your reading.

The receiving side does not change at that moment, because it never was exempt. Which is the quiet lesson of the whole Kleinunternehmer chapter: build the receiving basics once, lightly, and the mandate holds no surprises at any size.

Reading about formats is one thing; an accounts-payable inbox full of them is another. Two free resources and one production path:

• Peppol e-Invoice Extractor: pull the seller, buyer, line items, VAT breakdown, and totals out of an e-invoice, free in the browser
• Peppol e-invoice extraction guide: the EN 16931 field model (Business Terms) explained field by field
• Invoice parsing with schema validation: process XRechnung, ZUGFeRD, Peppol invoices, PDFs, and paper scans into one validated output schema, with confidence and provenance on every value