Writing Invoices as a Freelancer: The Complete Guide for 2025

The freedom as a freelancer is great - but with the first project also comes the first administrative hurdle: The invoice. Those who make mistakes here risk not only delays in payment but also trouble with the tax office.

In this guide, you'll learn everything you need to know to create legally compliant invoices - from mandatory information to the e-invoicing obligation.

1. Mandatory Information: What Must Be on the Invoice?

For the tax office (and your customer) to accept the invoice, the following points must be included according to § 14 Para. 4 UStG:

• Complete name and address (yours and your customer's)
• Tax number or your VAT identification number (USt-IdNr.)
• Issue date of the invoice
• Consecutive invoice number (uniquely assigned)
• Quantity and type of service (what did you do exactly?)
• Date of service (when was the project completed?)
• Remuneration and tax amount (broken down by tax rates)
• Payment term (optional but strongly recommended)

Tip: Use automated invoice numbers. This prevents duplications that could lead to problems during an audit.

The complete checklist can be found in our article Mandatory Information on Invoices. For calculating amounts, use our VAT calculator.

2. Special Case: The Small Business Regulation

Do you use the small business regulation (§ 19 UStG)? Then you may not show VAT. Your invoice must instead include a note, for example:

"No VAT is charged according to § 19 UStG."

With Clever Invoice, this note is automatically inserted when you activate the small business regulation in your settings.

3. The New E-Invoicing Obligation from 2025

Attention: Since January 1, 2025, all freelancers in Germany must be able to receive e-invoices. By 2027/2028, sending will also become mandatory for almost everyone. A simple PDF is then no longer sufficient in the B2B sector.

What Does This Mean for You?

• Now (2025): You must be able to receive and process e-invoices
• From 2027: Sending obligation for companies with over €800,000 revenue
• From 2028: Sending obligation for all - including small business owners

XRechnung and ZUGFeRD are the formats of the future. Learn more in our comparison XRechnung vs. ZUGFeRD.

Advantage for you: With tools like Clever Invoice, you're already technically on the safe side without having to learn XML code.

4. Avoiding Common Mistakes

We see these mistakes again and again with freelancer invoices:

• Missing service date: The invoice date alone is not sufficient - the date of service provision is mandatory
• Wrong tax rate: Always check whether 19%, 7%, or a tax exemption applies
• Illegible layouts: Your invoice is also your business card. A professional design creates trust
• Missing bank details: Make it easy for the customer to pay - IBAN prominently placed

Tips for faster payment can be found in our article 5 Tips for Faster Payment.

5. Word, Excel, or Software?

Many freelancers start with Word templates. But with a growing number of customers, manual typing becomes a source of errors and time waste.

With professional invoicing software:

• Mandatory information is automatically added
• GoBD-compliant archiving is ensured
• You create e-invoices at the push of a button
• You keep track of open payments

Finding the Right Hourly Rate

Before you write your first invoice, you should know your hourly rate. Set too low, and you're working below value. Too high, and you won't get orders.

Learn in our guide how to calculate your hourly rate correctly - with concrete formulas and examples.

Conclusion: Save Time for the Essentials

Writing invoices is part of freelancer everyday life, but shouldn't steal your evening. Once you've familiarized yourself with the mandatory information and use the right tool, accounting is done in a few minutes.

Are you ready? Create your first legally compliant invoice in less than 60 seconds - free and without credit card.