Everything you need to know about invoicing as a freelancer.
And how we take the work off your hands.
1. Mandatory Invoice Details – §14 UStG
Your client passes your invoice to accounting – and it comes back. Reason: missing tax ID, wrong service period or no VAT ID. Embarrassing? Definitely. Avoidable? Absolutely.
The Legal Situation
§14 UStG defines 11 mandatory details, including:
- Full name and address (invoicer + recipient)
- Tax number or VAT ID
- Invoice date and sequential invoice number
- Type and scope of service (e.g. „IT consulting“)
- Date or period of service
- Net amount, tax rate, tax amount, gross amount
How RuckZuckRechnung helps you:
- Automatic check of all 11 mandatory details before sending
- Sequential invoice numbers – gap-free and automatic
- Tax number is taken from your profile
- Service period as mandatory field – impossible to forget
2. Hourly Rate, Daily Rate, Project Flat Fee – Billing Correctly
„Just send me an invoice for the hours.“ Sounds simple – but it isn’t always. 80 hours at €95, plus 3 workshop days, travel costs and a documentation flat fee. Getting it all correct and traceable on one invoice?
The Legal Situation
§14 UStG requires a precise service description and the service period:
- List hours/days clearly (quantity × unit × price)
- Specify service period (e.g. „01.03. – 31.03.2026“)
- Show travel costs separately (recommended)
- For partial invoices: label as such, reference the overall contract
How RuckZuckRechnung helps you:
- Flexible line items – hours, days or flat fees with custom descriptions
- Travel costs as separate items – clearly separated
- Professional presentation with subtotals and grand total
- Partial invoices and instalment invoices supported
3. E-Invoice & ZUGFeRD – The New Requirement
Your client is a company? Then e-invoicing becomes relevant for you. From 2028, all B2B invoices in Germany must be sent as structured e-invoices – in ZUGFeRD or XRechnung format. A simple PDF will no longer suffice.
The Legal Situation
- Since 01.01.2025: You must be able to receive e-invoices
- Until 31.12.2026: PDF sending still allowed with consent
- 2027 (revenue ≤ €800,000): PDF with consent still allowed
- From 01.01.2028: Only structured e-invoices to business clients
ZUGFeRD is ideal for freelancers: A normal PDF file with embedded XML data. Professional invoice + machine-readable data in one file.
How RuckZuckRechnung helps you:
- ZUGFeRD is already built in – every invoice is automatically an e-invoice
- Future-proof from today – no stress in 2027
- Client-compatible: SAP, DATEV and every modern accounting software
4. Small Business – Correctly Implementing §19 UStG
Just started or deliberately staying small? Many freelancers – especially coaches, trainers and creatives – use the small business regulation. It saves the VAT advance return. But beware: if you accidentally show VAT, you owe it to the tax office – even as a small business (§14c UStG).
The Legal Situation
§19 UStG exempts you from VAT if:
- Your revenue last year was ≤ €25,000 (raised since 2025)
- Your revenue this year is expected to stay ≤ €100,000
- No VAT shown – no tax rate, no tax amount
- Mandatory notice: „No VAT charged pursuant to §19 UStG.“
- All other mandatory details (§14 UStG) still apply
How RuckZuckRechnung helps you:
- Small business mode: activate once – all invoices without VAT
- Automatic §19 notice text on every invoice
- Revenue threshold in view – you’ll see in time when you’re approaching the limit
5. International Clients – Billing EU & Third Countries Correctly
Your client is in Amsterdam, London or New York? Then special rules apply to your invoice – depending on whether the client is in the EU or a third country and whether they are a business or private individual.
The Legal Situation
Services to businesses in the EU (B2B):
- Place of supply = recipient’s location (§3a para. 2 UStG)
- Reverse charge procedure applies: You invoice net
- Mandatory notice: „Reverse charge – VAT liability of the service recipient“
- Your VAT ID and the client’s must appear on the invoice
- Third country (UK, USA, Switzerland): Place of supply = recipient’s location → not taxable in Germany
- Notice: „Non-taxable other service pursuant to §3a para. 2 UStG“
How RuckZuckRechnung helps you:
- Client type detection: EU business or third country – automatically net with correct notice
- VAT ID field prominently on the invoice
- Multilingual invoices – English and 5 other languages
- Correct reverse charge and third-country notice text set automatically
6. Record Retention – §14b UStG & GoBD
Every invoice you issue must be kept for 10 years. Not just anywhere on your desktop – but GoBD-compliant: immutable, complete and accessible at any time. At the latest during a tax audit, this becomes a problem.
Your Obligations as Invoice Issuer
- 10 years retention obligation (§14b para. 1 UStG)
- Digital invoices must be archived digitally (printout is not enough!)
- GoBD requires: traceability, immutability, completeness
- No subsequent changes to stored invoices
How RuckZuckRechnung helps you:
- Automatic archive – all invoices are saved automatically
- GoBD-compliant: immutable storage, complete documentation
- Searchable: find any invoice in seconds – by client, date or amount
7. Late Payments & Dunning – Get Paid Faster
Freelancers wait an average of 30 to 60 days for their money. With large corporations often even longer. The problem: you finished the work long ago, but your account is empty. Sending reminders feels uncomfortable – so you wait. And your cash flow suffers.
The Legal Situation
- §286 BGB: Your client is automatically in default 30 days after due date
- §288 BGB: Default interest: 5% above base rate (private) or 9% above base rate (business clients)
- §288 para. 5 BGB: For B2B transactions additionally €40 flat fee
How RuckZuckRechnung helps you:
- Payment status at a glance – open, overdue or paid
- Automatic payment reminders – professionally worded
- Due date clearly on every invoice
- Dunning levels – from friendly reminder to formal demand
8. Professional Image & Bogus Self-Employment
Your invoice is often the only thing that remains after project completion. It sits in accounting, gets archived, sometimes forwarded. If it looks unprofessional, you leave a bad last impression.
Indicators of Genuine Self-Employment
Especially IT freelancers and consultants who work longer for just one client know the topic of bogus self-employment. Professional, independent invoicing is one of the indicators:
- Own invoice numbers (not dictated by the client)
- Own branding (logo, letterhead, business address)
- Billing by result (not by attendance)
- Multiple clients visible
How RuckZuckRechnung helps you:
- Professional templates with your logo, your colours, your branding
- Own invoice number logic – a clear indicator of self-employment
- Multilingual – invoices in German, English and 4 other languages
- Consistent appearance – whether €500 or €50,000
- Client management – different clients, cleanly separated. A strong signal to authorities
Problem identified. Solution built in.
| What concerns you | What RuckZuckRechnung does |
|---|---|
| §14 mandatory details – invoice gets returned | Automatic check of all 11 details |
| Hourly rate, daily rate, flat fee – all on one invoice? | Flexible line items, subtotals |
| E-invoice – mandatory from 2028 | ZUGFeRD built in from day 1 |
| §19 small business – accidental VAT shown | Small business switch |
| EU client or third country – wrong VAT = liability | Automatically net + notice text |
| Retention – 10 years, GoBD-compliant | Digital archive, automatic |
| Late payments – waiting 30–60 days | Payment tracking + reminders |
| Bogus self-employment – document indicators | Own numbers, branding, client management |
Try it out – free and without obligation.
Create your first invoice in under 5 minutes. All mandatory details and ZUGFeRD included. No subscription needed to test.
Try for free now