If a required detail is missing from an invoice, your customer has a problem: they may not be able to deduct the input VAT and will ask you for a corrected invoice. That costs time and delays payment. With this checklist you can check your invoices in two minutes. It is based on German VAT law.
Checklist: these details belong on every invoice
For invoices over EUR 250 to businesses, Section 14(4) of the German VAT Act (UStG) lists these details:
- Your name and address and your customer's, both in full. A PO box is sufficient as an address.
- Your tax number or your VAT ID number.
- Date of issue of the invoice.
- A sequential invoice number that is only used once. Letters and numbers are allowed, for example “2026-0042”.
- Quantity and type of the goods or services, specific enough that it is clear what is meant. “Various work” is not enough.
- Date of supply or service, meaning the date of service or the service period. If it is the same as the invoice date, a note such as “date of service equals invoice date” is sufficient.
- The net amount broken down by tax rate, plus any agreed discounts or early payment discounts unless already included in the price.
- Tax rate and tax amount, or a note explaining why no VAT is charged.
- A note on the obligation to keep the invoice if you carry out work on a house or property for private customers, for example as a tradesperson.
- The word “Gutschrift” (self-billing) if your customer issues the statement (self-billing procedure).
Notes for special cases
- Reverse charge (for example services to businesses in other EU countries): “reverse charge” (the recipient owes the tax) and the VAT ID numbers of both parties.
- Intra-Community supply of goods to another EU country: a note on the tax exemption and both VAT ID numbers.
- Tax-exempt services, for example certain medical or teaching services: a short note explaining why no tax is charged.
Small-amount invoices up to EUR 250
For invoices up to EUR 250 gross, simplified rules apply (Section 33 UStDV). These are enough:
- your name and address
- the date of issue
- quantity and type of service
- the total amount including tax and the tax rate, or a note on the tax exemption
The customer's name and address, invoice number and tax number are not required here. Small-amount invoices are also exempt from mandatory e-invoicing.
Invoices as a small business (Kleinunternehmer)
As a small business under Section 19 UStG, you don't show VAT. Instead, the invoice needs a note on the tax exemption, for example: “Gemäß § 19 UStG wird keine Umsatzsteuer berechnet” (no VAT charged under Section 19 UStG).
Since 2025, slightly simplified invoice details apply to small businesses. Even so, it is worth numbering invoices sequentially and giving complete details. That makes your own bookkeeping easier and avoids questions. Which details are enough in your case is best checked with your tax advisor. What e-invoicing means for small businesses is explained in the guide E-invoicing 2027 for small businesses.
The most common mistakes
- Date of service missing. The classic. The invoice date alone is not enough.
- Service described too vaguely. “Consulting” without a period or project is too little.
- Invoice number used twice, for example because two Excel templates are used side by side.
- Wrong tax rate or missing reverse charge note.
- Invoice changed after sending instead of being corrected with a cancellation invoice or credit note.
What applies to e-invoices?
The same required details apply to e-invoices. The difference: they are in fixed data fields instead of just text on the page. How this works is explained in Creating an e-invoice: step by step.
Want to avoid the typical mistakes from the start? In Invoice Studio the app numbers invoices in sequence without gaps, finished invoices are locked, and corrections go through a credit note. The invoice check shows you live when the date of service, your tax number or the VAT ID for reverse charge is missing. One click takes you straight to the field. Offline app, your data stays on your device, one-time purchase with no subscription.
Frequently asked questions
How quickly do I have to issue an invoice?
For services to businesses, within six months of the service. In your own interest it is worth invoicing much sooner.
Does the invoice number have to be without gaps?
It must be unique and assigned sequentially. You may use several number ranges, for example one per year.
What happens if a required detail is missing?
The invoice is still a claim your customer has to pay. But they may not be able to deduct the input VAT from it and will ask for a correction. The corrected invoice must refer to the original one.
Does an invoice need a signature?
No. A signature is not a required detail.
Have required details checked automatically
In Invoice Studio, the app checks every invoice while you write it: date of service, tax number, address, transposed digits in the IBAN, VAT notes and reverse charge. Invoice numbers run sequentially automatically, and finished invoices are locked so nothing gets changed by accident. If you like, it becomes an e-invoice as ZUGFeRD or XRechnung. The app runs offline with no subscription, and your data stays on your device.
This article is general guidance (as of October 2026) and is not tax advice. For your individual case, please talk to your tax advisor.