When You Are Allowed to Issue Invoices: Timing, Deadlines and Mandatory Details for Founders
The first invoice often feels like a small milestone: the idea has become an order, and now money is to flow for the first time. At the same time, nobody wants to make a formal mistake right at the start that later triggers corrections, queries or uncertainty.
What matters most is which formation phase you are in and whether your invoice meets the mandatory tax details.
Table of contents
At a glance
When you are allowed to issue invoices depends on the timing of the service and the status of your formation. You should know these points:
- Invoices are often issued after the service has been provided. Down payments or instalments can also be invoiced beforehand, depending on the agreement.
- For services to other businesses for their business or to legal entities, the invoice must generally be issued within six months of the service being performed.
- Before the notary appointment, your GmbH does not yet legally exist. Backdating invoices to the later company is not possible.
- Between notarisation and entry in the commercial register, the company can take part in business as a GmbH in formation. The suffix “i. G.” or “in formation” should be used.
- A proper invoice contains the mandatory details under Section 14 UStG, from the tax number to the sequential invoice number.
From when may founders issue invoices?
An invoice documents a service, a delivery or an agreed payment. In many cases it is issued after the service has been provided. For down payments or instalments, for example on longer projects, it can also be issued before the service is completed if this has been agreed. Such advance invoices should be recognisable as such and are taken into account in the final invoice.
The prerequisite is that the activity is registered for tax purposes and, where required, registered as a trade. Which registration is necessary depends on the activity and the legal form. How tax registration works is explained in our article on registering with the tax office. The start-up portal of the Federal Ministry for Economic Affairs (existenzgruender.de) also offers a neutral introduction to the basics.
Invoicing before GmbH registration: what applies in which formation phase?
A particularly large number of questions arise when the first orders are already underway but the GmbH is not yet in the commercial register. This is a very typical situation, as hardly any founder waits with acquisition until all formalities are completed. What matters is which phase of the formation you are in.
Before the notary appointment: the GmbH does not yet exist
As long as the articles of association have not been notarised, your GmbH does not legally exist. Anyone already providing services during this time is usually acting personally or, where several persons are involved, possibly in a pre-formation company. Which legal classification applies in the individual case should be checked if in doubt. Invoices can be issued on this basis if the activity is registered for tax purposes accordingly and, where required, registered as a trade.
What does not work: subsequently attributing services from this period to the later GmbH. There is no retroactive tax effect for the period before the notary appointment, so backdating invoices is not an option. What this means for your personal liability is explained in our article on liability before registration.
Issuing invoices as a GmbH in formation
With notarisation, the so-called GmbH in formation, or GmbH i. G. for short, comes into existence. It can already take part in business. For tax purposes, the phase between the notarial deed and entry in the commercial register is usually treated as if the GmbH had existed since the notarial deed, so invoices can be issued on this basis.
Uncertainty is often particularly high in this phase: the formation is already underway but not yet completed. It is therefore important to make clear externally that the company is still in formation, for example by using the suffix “GmbH i. G.”. Also note that special liability questions can arise in this phase.
Apply for the tax number as soon as possible after the notary appointment via the tax registration questionnaire, which you submit online via ELSTER. Since the tax number or VAT identification number is one of the mandatory details, the first invoice showing VAT should ideally only be issued once one of these numbers is available. If you have to invoice before then, it is best to agree the approach with your tax adviser and correct the invoice later if necessary.
Many founders would like to write their first invoice directly after the notary appointment, but the business account for receiving payment is often still missing. So take care of opening the account early, because without the share capital paid in, registration cannot proceed either. How this works is shown in our article on opening a business bank account.
After registration: use complete details
After registration, the suffix “i. G.” is dropped and the company acts as a GmbH. Business letters and invoices should now carry the complete company details, in particular the company name, legal form, registered office, register court, commercial register number and management. For invoices, the mandatory details under Section 14 UStG are added. Invoices you previously issued correctly as a GmbH i. G. do not have to be rewritten. Our article on the structure of a company gives an overview of your company’s structure.
These deadlines apply to your invoices
When it comes to the timing of invoicing, there is not only a “from when” but also a “by when”. This is easily overlooked in the day-to-day of a start-up when other issues are pressing.
- Services to businesses and legal entities: For services to other businesses for their business or to legal entities, the invoice must generally be issued within six months of the service being performed. This deadline follows from the VAT Act.
- Services to private customers: Here there is usually no statutory obligation to issue an invoice. One exception concerns in particular certain services in connection with a property, such as construction or trade services. The six-month deadline generally applies to such cases as well.
Regardless of these deadlines, it is worth invoicing promptly. Payment claims usually become time-barred after three years, with the period generally starting only at the end of the year in which the claim arose. Especially in the initial phase, liquidity is often the decisive factor. Anyone who leaves invoices lying around for months gives away predictability and risks unnecessary discussions with customers.
Mandatory details: what belongs on every invoice
For an invoice to be proper for tax purposes and for your customer to be able to claim input tax, it must contain the mandatory details under Section 14 UStG:
- full name and full address of the supplier and the recipient
- tax number or VAT identification number
- date of issue
- sequential invoice number
- quantity and type of goods delivered or scope and type of other service
- date of delivery or other service
- consideration broken down by tax rates and tax exemptions
- applicable tax rate and tax amount, or a reference to a tax exemption
- for advance payments: the date of receipt, if it is fixed and does not match the date of issue
Useful additions
In practice, a clear payment term, your bank details, contact details and the clear designation as “invoice” have also proven useful. For transactions with businesses in other EU countries, the reverse charge procedure may apply: then both VAT identification numbers belong on the invoice, along with the note “VAT liability of the recipient” (Steuerschuldnerschaft des Leistungsempfängers). Such cases are best clarified with your tax adviser.
Special cases: small businesses and low-value invoices
If you use the small business scheme under Section 19 UStG, you do not show VAT. The invoice should state that no VAT is charged under Section 19 UStG.
Simplified requirements under Section 33 UStDV apply to invoices up to 250 euros gross. Required are, among other things, the name and address of the supplier, the date of issue, the type and scope of the service, the gross amount and the applicable tax rate or a reference to a tax exemption.
E-invoicing: what currently applies
Since 1 January 2025, e-invoicing has generally applied to transactions between domestic businesses. Businesses must be able to receive e-invoices. Transitional rules apply to issuing them: until the end of 2026, paper invoices or simple PDF invoices may still be used under certain conditions. For businesses with a prior-year turnover of up to 800,000 euros, an extended transitional period applies until the end of 2027. From 2028, the e-invoicing obligation will generally apply comprehensively in the B2B sector. Small businesses are exempt from the obligation to issue e-invoices but must be able to receive them. Private end customers are not affected by the e-invoicing obligation.
For founders, this means: rely from the start on invoicing software that can create and receive e-invoices. Then you are better prepared for the upcoming requirements.
Typical mistakes when issuing invoices
Many mistakes arise not from carelessness but because a lot happens at the same time in the formation phase: notary appointment, business account, tax number, first orders and first customer conversations. A clear sequence helps you keep track. These points are most often overlooked:
- The invoice number is missing or assigned twice.
- The date of service is not stated; the invoice date alone is not enough.
- Addresses are incomplete or outdated.
- The invoice is issued showing VAT before the tax number or VAT identification number is available and has to be corrected later.
- Services from the period before the notary appointment are attributed to the GmbH.
- The company acts before registration without the suffix “in formation”.
- The reference to the small business scheme is missing, or VAT is shown even though the scheme is used.
- The required note is missing on reverse charge transactions.
- The six-month deadline for business with other businesses is overlooked.
More from the series: the notary appointment
Arrange a notary appointment
We are happy to support you in preparing and carrying out your formation with legal certainty. Arrange a notary appointment early to clarify open questions and plan the process in a structured way.
Frequently asked questions about issuing invoices
Yes, after notarisation the GmbH in formation can generally take part in business and issue invoices, with the suffix “i. G.”. Before the notary appointment, the GmbH does not yet exist; services from this phase must be attributed differently.
No. For services before the notary appointment, there is no retroactive tax effect for the later GmbH. You invoice these services personally or via the company existing at the time.
The tax number or VAT identification number is one of the mandatory details of a proper invoice. If no number is available yet, it is best to agree the approach with your tax adviser and correct the invoice later if necessary.
Issuing an invoice late can have tax consequences and may be treated as an administrative offence. The payment claim is not automatically lost as a result, but you should still invoice promptly.
Usually not; a statutory obligation exists mainly for certain services in connection with a property. An invoice is nevertheless almost always sensible, if only for your own bookkeeping and a professional appearance.
Since 2025, e-invoicing has applied to transactions between domestic businesses, with transitional rules for issuing until the end of 2027 at the latest. Small businesses must be able to receive e-invoices but are exempt from the obligation to issue them.
Daniel ★ ★ ★ ★ ★
“Mr Franke and his team are extremely friendly and competent, and processing is very fast and reliable.”
Properly set up from the first invoice
When you are allowed to issue invoices is closely linked to the status of your formation. Especially between the notary appointment, business account, tax number and first invoice, a clear sequence helps. This way you avoid later corrections and appear professional to customers from the start.
Notary Franke supports your GmbH formation from notarisation to the commercial register application. Detailed tax questions on invoices, VAT and e-invoicing are best clarified additionally with your tax adviser.
