How Can I Change My Invoice Number?

Gekko uses a standard invoice numbering system formatted as follows:

2025-000001, 2025-000002, etc.
2025-000012, 2025-000013, etc.

At the turn of the year, Gekko automatically updates the standard invoice numbering to the new year. 

For example, 2025-000123 can change to 2026-000001.

Easily Create invoices with Gekko.

Adjusting Your Invoice Number

Follow these steps to adjust your invoice numbering:

1. Go to the invoice overview on the Gekko website.
   
   
2. Click the '+New' button at the top right to create a new invoice.
   
   
3. While editing the invoice, click on 'Details' or directly on the invoice number.
   
   
   
4. A pop-up window will appear where you can change your invoice number.
   
   
   
5. Click 'Accept' to save the changes.
   
   

Once you have saved your invoice, the following invoices will continue with the new numbering sequence. Ideally, you only need to adjust and save the invoice number once.

Using Your Own Invoice Numbering

If you want to use your own invoice numbering (or are already using one), note that the year in the invoice number will not be updated automatically at the start of a new year. In this case, you must manually adjust your numbering to reflect the new year.

Gekko follows the last numeric part of your invoice number for automatic sequencing.

For example:

• If your invoice number is MYCOMPANY001, Gekko will automatically generate MYCOMPANY002 for the next invoice.
• Gekko always takes the last numerical part of the invoice number.

Important Considerations:

• If you include a year in your invoice number, ensure you use enough digits.
  • Example: If you use 202501, and the count exceeds 100, Gekko may generate 202601, even if it is still 2025.
• You can use letters in your invoice number, but numbering always follows the numeric sequence.
• Gekko only increments the last numerical partof the invoice number.
  • Example: If your invoice is 0001-2019, the next might be 0001-2020.
    
    
  • If your invoice is 00001MYCOMPANY, the next may be 00001MYCOMPANY1.
    
    
  • To avoid confusion, keep the numbering at the end of the invoice number.
    
    

Using a custom invoice numbering system is fine, but remember you must manually update it at the start of a new year. Gekko cannot always distinguish between a year, a number, or text in a custom invoice number.

Automatic Invoice Numbering in Gekko

By default, Gekko uses the format: <>-000001. If unchanged, Gekko will automatically continue both the sequential number and the year.

For example:

• If you create an invoice in 2025, the next will be 2025-000002.
• If you create a new invoice in 2026, it will automatically start at 2026-000001.

Some users prefer a custom invoice number format. While this is possible, Gekko may not always know how to continue the numbering correctly.

Made a Mistake? No Problem!

If you made a mistake in your invoice numbering, you can easily correct it.
Check out the FAQ on credit invoices for more details.

Sending an Invoice with a Previous Year's Number

At the start of a new year, you might still need to send an invoice for the previous year.

Can you record this in December?

Technically, yes—as long as it's reasonable.

• It's generally acceptable to issue an invoice for December in early January, as you might still be closing your books.
• However, the work must have actually been completed in the previous year.
• The Dutch Tax Authority (Belastingdienst) monitors this strictly to prevent shifting revenue between years to manipulate taxes.

After one month into the new year, it is not recommended to issue invoices for the previous year.

When creating a new invoice in Gekko, it will suggest the new year in the invoice number.
You can manually adjust the invoice number and date to reflect the previous year.

Be careful with subsequent invoices:

• If you change the invoice number back to the previous year, Gekko will continue numbering from that format.
• You may need to manually adjust the next invoice number again to ensure it reflects the correct year.

For more information on invoice regulations, visit the Dutch Tax Authority website.

Backdating an Invoice

Changing the date on an invoice after it has been issued is not allowed.
Creating an invoice with a past date is called backdating and is prohibited.

For more details, check the Tax Wiki on backdating invoices.